diff --git a/bin/node/runtime/src/lib.rs b/bin/node/runtime/src/lib.rs
index 2d5825abc906c..27f2516254f0f 100644
--- a/bin/node/runtime/src/lib.rs
+++ b/bin/node/runtime/src/lib.rs
@@ -483,6 +483,7 @@ parameter_types! {
 	// One cent: $10,000 / MB
 	pub const PreimageByteDeposit: Balance = 1 * CENTS;
 	pub const MaxVotes: u32 = 100;
+	pub const MaxProposals: u32 = 100;
 }
 
 impl pallet_democracy::Trait for Runtime {
@@ -508,6 +509,14 @@ impl pallet_democracy::Trait for Runtime {
 	type FastTrackVotingPeriod = FastTrackVotingPeriod;
 	// To cancel a proposal which has been passed, 2/3 of the council must agree to it.
 	type CancellationOrigin = pallet_collective::EnsureProportionAtLeast<_2, _3, AccountId, CouncilCollective>;
+	// To cancel a proposal before it has been passed, the technical committee must be unanimous or
+	// Root must agree.
+	type CancelProposalOrigin = EnsureOneOf<
+		AccountId,
+		EnsureRoot<AccountId>,
+		pallet_collective::EnsureProportionAtLeast<_1, _1, AccountId, TechnicalCollective>,
+	>;
+	type BlacklistOrigin = EnsureRoot<AccountId>;
 	// Any single technical committee member may veto a coming council proposal, however they can
 	// only do it once and it lasts only for the cooloff period.
 	type VetoOrigin = pallet_collective::EnsureMember<AccountId, TechnicalCollective>;
@@ -519,6 +528,7 @@ impl pallet_democracy::Trait for Runtime {
 	type PalletsOrigin = OriginCaller;
 	type MaxVotes = MaxVotes;
 	type WeightInfo = weights::pallet_democracy::WeightInfo<Runtime>;
+	type MaxProposals = MaxProposals;
 }
 
 parameter_types! {
diff --git a/bin/node/runtime/src/weights/pallet_democracy.rs b/bin/node/runtime/src/weights/pallet_democracy.rs
index b02da3f53a7f9..51eca2855a384 100644
--- a/bin/node/runtime/src/weights/pallet_democracy.rs
+++ b/bin/node/runtime/src/weights/pallet_democracy.rs
@@ -1,3 +1,5 @@
+// This file is part of Substrate.
+
 // Copyright (C) 2020 Parity Technologies (UK) Ltd.
 // SPDX-License-Identifier: Apache-2.0
 
@@ -13,8 +15,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Weights for the Democracy Pallet
-//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 2.0.0-rc5
+//! Weights for pallet_democracy
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 2.0.0
+//! DATE: 2020-09-24, STEPS: [50], REPEAT: 20, LOW RANGE: [], HIGH RANGE: []
+
+#![allow(unused_parens)]
+#![allow(unused_imports)]
 
 use frame_support::{traits::Get, weights::Weight};
 use sp_std::marker::PhantomData;
@@ -22,134 +28,145 @@ use sp_std::marker::PhantomData;
 pub struct WeightInfo<T>(PhantomData<T>);
 impl<T: frame_system::Trait> pallet_democracy::WeightInfo for WeightInfo<T> {
 	fn propose() -> Weight {
-		(49113000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(2 as Weight))
+		(96_316_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn second(s: u32, ) -> Weight {
-		(42067000 as Weight)
-			.saturating_add((220000 as Weight).saturating_mul(s as Weight))
+		(58_386_000 as Weight)
+			.saturating_add((259_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn vote_new(r: u32, ) -> Weight {
-		(54159000 as Weight)
-			.saturating_add((252000 as Weight).saturating_mul(r as Weight))
+		(70_374_000 as Weight)
+			.saturating_add((291_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn vote_existing(r: u32, ) -> Weight {
-		(54145000 as Weight)
-			.saturating_add((262000 as Weight).saturating_mul(r as Weight))
+		(70_097_000 as Weight)
+			.saturating_add((296_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn emergency_cancel() -> Weight {
-		(31071000 as Weight)
+		(41_731_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
+	fn blacklist(p: u32, ) -> Weight {
+		(117_847_000 as Weight)
+			.saturating_add((871_000 as Weight).saturating_mul(p as Weight))
+			.saturating_add(T::DbWeight::get().reads(5 as Weight))
+			.saturating_add(T::DbWeight::get().writes(6 as Weight))
+	}
 	fn external_propose(v: u32, ) -> Weight {
-		(14282000 as Weight)
-			.saturating_add((109000 as Weight).saturating_mul(v as Weight))
+		(20_972_000 as Weight)
+			.saturating_add((114_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn external_propose_majority() -> Weight {
-		(3478000 as Weight)
+		(5_030_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn external_propose_default() -> Weight {
-		(3442000 as Weight)
+		(4_981_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn fast_track() -> Weight {
-		(30820000 as Weight)
+		(42_801_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn veto_external(v: u32, ) -> Weight {
-		(30971000 as Weight)
-			.saturating_add((184000 as Weight).saturating_mul(v as Weight))
+		(44_115_000 as Weight)
+			.saturating_add((194_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
+	fn cancel_proposal(p: u32, ) -> Weight {
+		(73_937_000 as Weight)
+			.saturating_add((962_000 as Weight).saturating_mul(p as Weight))
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
+			.saturating_add(T::DbWeight::get().writes(3 as Weight))
+	}
 	fn cancel_referendum() -> Weight {
-		(20431000 as Weight)
+		(25_233_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn cancel_queued(r: u32, ) -> Weight {
-		(42438000 as Weight)
-			.saturating_add((3284000 as Weight).saturating_mul(r as Weight))
+		(48_251_000 as Weight)
+			.saturating_add((3_590_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn on_initialize_base(r: u32, ) -> Weight {
-		(70826000 as Weight)
-			.saturating_add((10716000 as Weight).saturating_mul(r as Weight))
-			.saturating_add(T::DbWeight::get().reads(6 as Weight))
-			.saturating_add(T::DbWeight::get().reads((2 as Weight).saturating_mul(r as Weight)))
-			.saturating_add(T::DbWeight::get().writes(5 as Weight))
+		(17_597_000 as Weight)
+			.saturating_add((7_248_000 as Weight).saturating_mul(r as Weight))
+			.saturating_add(T::DbWeight::get().reads(5 as Weight))
+			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn delegate(r: u32, ) -> Weight {
-		(72046000 as Weight)
-			.saturating_add((7837000 as Weight).saturating_mul(r as Weight))
+		(93_916_000 as Weight)
+			.saturating_add((10_794_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(4 as Weight))
 			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 			.saturating_add(T::DbWeight::get().writes(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn undelegate(r: u32, ) -> Weight {
-		(41028000 as Weight)
-			.saturating_add((7810000 as Weight).saturating_mul(r as Weight))
+		(47_855_000 as Weight)
+			.saturating_add((10_805_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn clear_public_proposals() -> Weight {
-		(3643000 as Weight)
+		(4_864_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn note_preimage(b: u32, ) -> Weight {
-		(46629000 as Weight)
-			.saturating_add((4000 as Weight).saturating_mul(b as Weight))
+		(66_754_000 as Weight)
+			.saturating_add((4_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn note_imminent_preimage(b: u32, ) -> Weight {
-		(31147000 as Weight)
-			.saturating_add((3000 as Weight).saturating_mul(b as Weight))
+		(44_664_000 as Weight)
+			.saturating_add((3_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn reap_preimage(b: u32, ) -> Weight {
-		(42848000 as Weight)
-			.saturating_add((3000 as Weight).saturating_mul(b as Weight))
+		(59_968_000 as Weight)
+			.saturating_add((3_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn unlock_remove(r: u32, ) -> Weight {
-		(45333000 as Weight)
-			.saturating_add((171000 as Weight).saturating_mul(r as Weight))
+		(58_573_000 as Weight)
+			.saturating_add((131_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn unlock_set(r: u32, ) -> Weight {
-		(44424000 as Weight)
-			.saturating_add((291000 as Weight).saturating_mul(r as Weight))
+		(53_831_000 as Weight)
+			.saturating_add((324_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn remove_vote(r: u32, ) -> Weight {
-		(28250000 as Weight)
-			.saturating_add((283000 as Weight).saturating_mul(r as Weight))
+		(31_846_000 as Weight)
+			.saturating_add((327_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn remove_other_vote(r: u32, ) -> Weight {
-		(28250000 as Weight)
-			.saturating_add((283000 as Weight).saturating_mul(r as Weight))
+		(31_880_000 as Weight)
+			.saturating_add((222_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
diff --git a/frame/benchmarking/src/utils.rs b/frame/benchmarking/src/utils.rs
index 347334e24d5f6..042f4b707aef4 100644
--- a/frame/benchmarking/src/utils.rs
+++ b/frame/benchmarking/src/utils.rs
@@ -219,3 +219,12 @@ pub fn account<AccountId: Decode + Default>(name: &'static str, index: u32, seed
 pub fn whitelisted_caller<AccountId: Decode + Default>() -> AccountId {
 	account::<AccountId>("whitelisted_caller", 0, 0)
 }
+
+#[macro_export]
+macro_rules! whitelist_account {
+	($acc:ident) => {
+		frame_benchmarking::benchmarking::add_to_whitelist(
+			frame_system::Account::<T>::hashed_key_for(&$acc).into()
+		);
+	}
+}
diff --git a/frame/democracy/src/benchmarking.rs b/frame/democracy/src/benchmarking.rs
index 1fa0988fbbd4d..0b822e885989e 100644
--- a/frame/democracy/src/benchmarking.rs
+++ b/frame/democracy/src/benchmarking.rs
@@ -19,7 +19,7 @@
 
 use super::*;
 
-use frame_benchmarking::{benchmarks, account};
+use frame_benchmarking::{benchmarks, account, whitelist_account};
 use frame_support::{
 	IterableStorageMap,
 	traits::{Currency, Get, EnsureOrigin, OnInitialize, UnfilteredDispatchable, schedule::DispatchTime},
@@ -30,7 +30,7 @@ use sp_runtime::traits::{Bounded, One};
 use crate::Module as Democracy;
 
 const SEED: u32 = 0;
-const MAX_REFERENDUMS: u32 = 100;
+const MAX_REFERENDUMS: u32 = 99;
 const MAX_SECONDERS: u32 = 100;
 const MAX_BYTES: u32 = 16_384;
 
@@ -63,7 +63,7 @@ fn add_proposal<T: Trait>(n: u32) -> Result<T::Hash, &'static str> {
 }
 
 fn add_referendum<T: Trait>(n: u32) -> Result<ReferendumIndex, &'static str> {
-	let proposal_hash = add_proposal::<T>(n)?;
+	let proposal_hash: T::Hash = T::Hashing::hash_of(&n);
 	let vote_threshold = VoteThreshold::SimpleMajority;
 
 	Democracy::<T>::inject_referendum(
@@ -100,12 +100,19 @@ benchmarks! {
 	_ { }
 
 	propose {
+		let p = T::MaxProposals::get();
+
+		for i in 0 .. (p - 1) {
+			add_proposal::<T>(i)?;
+		}
+
 		let caller = funded_account::<T>("caller", 0);
 		let proposal_hash: T::Hash = T::Hashing::hash_of(&0);
 		let value = T::MinimumDeposit::get();
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller), proposal_hash, value.into())
 	verify {
-		assert_eq!(Democracy::<T>::public_props().len(), 1, "Proposals not created.");
+		assert_eq!(Democracy::<T>::public_props().len(), p as usize, "Proposals not created.");
 	}
 
 	second {
@@ -122,6 +129,7 @@ benchmarks! {
 
 		let deposits = Democracy::<T>::deposit_of(0).ok_or("Proposal not created")?;
 		assert_eq!(deposits.0.len(), (s + 1) as usize, "Seconds not recorded");
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller), 0, u32::max_value())
 	verify {
 		let deposits = Democracy::<T>::deposit_of(0).ok_or("Proposal not created")?;
@@ -146,7 +154,7 @@ benchmarks! {
 		assert_eq!(votes.len(), r as usize, "Votes were not recorded.");
 
 		let referendum_index = add_referendum::<T>(r)?;
-
+		whitelist_account!(caller);
 	}: vote(RawOrigin::Signed(caller.clone()), referendum_index, account_vote)
 	verify {
 		let votes = match VotingOf::<T>::get(&caller) {
@@ -179,6 +187,7 @@ benchmarks! {
 		let referendum_index = Democracy::<T>::referendum_count() - 1;
 
 		// This tests when a user changes a vote
+		whitelist_account!(caller);
 	}: vote(RawOrigin::Signed(caller.clone()), referendum_index, new_vote)
 	verify {
 		let votes = match VotingOf::<T>::get(&caller) {
@@ -206,6 +215,31 @@ benchmarks! {
 		assert!(Democracy::<T>::referendum_status(referendum_index).is_err());
 	}
 
+	blacklist {
+		let p in 1 .. T::MaxProposals::get();
+
+		// Place our proposal at the end to make sure it's worst case.
+		for i in 0 .. p - 1 {
+			add_proposal::<T>(i)?;
+		}
+		// We should really add a lot of seconds here, but we're not doing it elsewhere.
+
+		// Place our proposal in the external queue, too.
+		let hash = T::Hashing::hash_of(&0);
+		assert!(Democracy::<T>::external_propose(T::ExternalOrigin::successful_origin(), hash.clone()).is_ok());
+
+		// Add a referendum of our proposal.
+		let referendum_index = add_referendum::<T>(0)?;
+		assert!(Democracy::<T>::referendum_status(referendum_index).is_ok());
+
+		let call = Call::<T>::blacklist(hash, Some(referendum_index));
+		let origin = T::BlacklistOrigin::successful_origin();
+	}: { call.dispatch_bypass_filter(origin)? }
+	verify {
+		// Referendum has been canceled
+		assert!(Democracy::<T>::referendum_status(referendum_index).is_err());
+	}
+
 	// Worst case scenario, we external propose a previously blacklisted proposal
 	external_propose {
 		let v in 1 .. MAX_VETOERS as u32;
@@ -287,6 +321,15 @@ benchmarks! {
 		assert_eq!(new_vetoers.len(), (v + 1) as usize, "vetoers not added");
 	}
 
+	cancel_proposal {
+		let p in 1 .. T::MaxProposals::get();
+
+		// Place our proposal at the end to make sure it's worst case.
+		for i in 0 .. p {
+			add_proposal::<T>(i)?;
+		}
+	}: _(RawOrigin::Root, 0)
+
 	cancel_referendum {
 		let referendum_index = add_referendum::<T>(0)?;
 	}: _(RawOrigin::Root, referendum_index)
@@ -301,7 +344,8 @@ benchmarks! {
 		let referendum_index = add_referendum::<T>(r)?;
 	}: _(RawOrigin::Root, referendum_index)
 
-	// Note that we have a separate benchmark for `launch_next`
+	// This measures the path of `launch_next` external. Not currently used as we simply
+	// assume the weight is `MaxBlockWeight` when executing.
 	#[extra]
 	on_initialize_external {
 		let r in 0 .. MAX_REFERENDUMS;
@@ -341,6 +385,8 @@ benchmarks! {
 		}
 	}
 
+	// This measures the path of `launch_next` public. Not currently used as we simply
+	// assume the weight is `MaxBlockWeight` when executing.
 	#[extra]
 	on_initialize_public {
 		let r in 1 .. MAX_REFERENDUMS;
@@ -352,6 +398,7 @@ benchmarks! {
 		assert_eq!(Democracy::<T>::referendum_count(), r, "referenda not created");
 
 		// Launch public
+		assert!(add_proposal::<T>(r).is_ok(), "proposal not created");
 		LastTabledWasExternal::put(true);
 
 		let block_number = T::LaunchPeriod::get();
@@ -359,7 +406,7 @@ benchmarks! {
 	}: { Democracy::<T>::on_initialize(block_number) }
 	verify {
 		// One extra because of next public
-		assert_eq!(Democracy::<T>::referendum_count(), r + 1, "referenda not created");
+		assert_eq!(Democracy::<T>::referendum_count(), r + 1, "proposal not accepted");
 
 		// All should be finished
 		for i in 0 .. r {
@@ -437,6 +484,7 @@ benchmarks! {
 			_ => return Err("Votes are not direct"),
 		};
 		assert_eq!(votes.len(), r as usize, "Votes were not recorded.");
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller.clone()), new_delegate.clone(), Conviction::Locked1x, delegated_balance)
 	verify {
 		let (target, balance) = match VotingOf::<T>::get(&caller) {
@@ -488,6 +536,7 @@ benchmarks! {
 			_ => return Err("Votes are not direct"),
 		};
 		assert_eq!(votes.len(), r as usize, "Votes were not recorded.");
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller.clone()))
 	verify {
 		// Voting should now be direct
@@ -508,6 +557,7 @@ benchmarks! {
 
 		let caller = funded_account::<T>("caller", 0);
 		let encoded_proposal = vec![1; b as usize];
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller), encoded_proposal.clone())
 	verify {
 		let proposal_hash = T::Hashing::hash(&encoded_proposal[..]);
@@ -529,6 +579,7 @@ benchmarks! {
 
 		let caller = funded_account::<T>("caller", 0);
 		let encoded_proposal = vec![1; b as usize];
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller), encoded_proposal.clone())
 	verify {
 		let proposal_hash = T::Hashing::hash(&encoded_proposal[..]);
@@ -555,6 +606,7 @@ benchmarks! {
 		assert!(Preimages::<T>::contains_key(proposal_hash));
 
 		let caller = funded_account::<T>("caller", 0);
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller), proposal_hash.clone(), u32::max_value())
 	verify {
 		let proposal_hash = T::Hashing::hash(&encoded_proposal[..]);
@@ -577,6 +629,7 @@ benchmarks! {
 		}
 
 		let caller = funded_account::<T>("caller", 0);
+		whitelist_account!(caller);
 	}: unlock(RawOrigin::Signed(caller), locker.clone())
 	verify {
 		// Note that we may want to add a `get_lock` api to actually verify
@@ -614,6 +667,7 @@ benchmarks! {
 		Democracy::<T>::remove_vote(RawOrigin::Signed(locker.clone()).into(), referendum_index)?;
 
 		let caller = funded_account::<T>("caller", 0);
+		whitelist_account!(caller);
 	}: unlock(RawOrigin::Signed(caller), locker.clone())
 	verify {
 		let votes = match VotingOf::<T>::get(&locker) {
@@ -645,7 +699,7 @@ benchmarks! {
 		assert_eq!(votes.len(), r as usize, "Votes not created");
 
 		let referendum_index = r - 1;
-
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller.clone()), referendum_index)
 	verify {
 		let votes = match VotingOf::<T>::get(&caller) {
@@ -674,7 +728,7 @@ benchmarks! {
 		assert_eq!(votes.len(), r as usize, "Votes not created");
 
 		let referendum_index = r - 1;
-
+		whitelist_account!(caller);
 	}: _(RawOrigin::Signed(caller.clone()), caller.clone(), referendum_index)
 	verify {
 		let votes = match VotingOf::<T>::get(&caller) {
@@ -765,6 +819,8 @@ mod tests {
 			assert_ok!(test_benchmark_remove_other_vote::<Test>());
 			assert_ok!(test_benchmark_enact_proposal_execute::<Test>());
 			assert_ok!(test_benchmark_enact_proposal_slash::<Test>());
+			assert_ok!(test_benchmark_blacklist::<Test>());
+			assert_ok!(test_benchmark_cancel_proposal::<Test>());
 		});
 	}
 }
diff --git a/frame/democracy/src/default_weight.rs b/frame/democracy/src/default_weight.rs
index 2c74a4af2020f..28aa45ae2d603 100644
--- a/frame/democracy/src/default_weight.rs
+++ b/frame/democracy/src/default_weight.rs
@@ -15,143 +15,156 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Default weights for the Democracy Pallet
-//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 2.0.0-rc5
+//! Weights for pallet_democracy
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 2.0.0
+//! DATE: 2020-09-24, STEPS: [50], REPEAT: 20, LOW RANGE: [], HIGH RANGE: []
+
+#![allow(unused_parens)]
+#![allow(unused_imports)]
 
 use frame_support::weights::{Weight, constants::RocksDbWeight as DbWeight};
 
-/// Default implementation of weight, this is just from an example return, values may change
-/// depending on the runtime. This is not meant to be used in production.
 impl crate::WeightInfo for () {
 	fn propose() -> Weight {
-		(49113000 as Weight)
-			.saturating_add(DbWeight::get().reads(2 as Weight))
+		(96_316_000 as Weight)
+			.saturating_add(DbWeight::get().reads(3 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn second(s: u32, ) -> Weight {
-		(42067000 as Weight)
-			.saturating_add((220000 as Weight).saturating_mul(s as Weight))
+		(58_386_000 as Weight)
+			.saturating_add((259_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(DbWeight::get().reads(1 as Weight))
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn vote_new(r: u32, ) -> Weight {
-		(54159000 as Weight)
-			.saturating_add((252000 as Weight).saturating_mul(r as Weight))
+		(70_374_000 as Weight)
+			.saturating_add((291_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(3 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn vote_existing(r: u32, ) -> Weight {
-		(54145000 as Weight)
-			.saturating_add((262000 as Weight).saturating_mul(r as Weight))
+		(70_097_000 as Weight)
+			.saturating_add((296_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(3 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn emergency_cancel() -> Weight {
-		(31071000 as Weight)
+		(41_731_000 as Weight)
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
+	fn blacklist(p: u32, ) -> Weight {
+		(117_847_000 as Weight)
+			.saturating_add((871_000 as Weight).saturating_mul(p as Weight))
+			.saturating_add(DbWeight::get().reads(5 as Weight))
+			.saturating_add(DbWeight::get().writes(6 as Weight))
+	}
 	fn external_propose(v: u32, ) -> Weight {
-		(14282000 as Weight)
-			.saturating_add((109000 as Weight).saturating_mul(v as Weight))
+		(20_972_000 as Weight)
+			.saturating_add((114_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn external_propose_majority() -> Weight {
-		(3478000 as Weight)
+		(5_030_000 as Weight)
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn external_propose_default() -> Weight {
-		(3442000 as Weight)
+		(4_981_000 as Weight)
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn fast_track() -> Weight {
-		(30820000 as Weight)
+		(42_801_000 as Weight)
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn veto_external(v: u32, ) -> Weight {
-		(30971000 as Weight)
-			.saturating_add((184000 as Weight).saturating_mul(v as Weight))
+		(44_115_000 as Weight)
+			.saturating_add((194_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
+	fn cancel_proposal(p: u32, ) -> Weight {
+		(73_937_000 as Weight)
+			.saturating_add((962_000 as Weight).saturating_mul(p as Weight))
+			.saturating_add(DbWeight::get().reads(3 as Weight))
+			.saturating_add(DbWeight::get().writes(3 as Weight))
+	}
 	fn cancel_referendum() -> Weight {
-		(20431000 as Weight)
+		(25_233_000 as Weight)
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn cancel_queued(r: u32, ) -> Weight {
-		(42438000 as Weight)
-			.saturating_add((3284000 as Weight).saturating_mul(r as Weight))
+		(48_251_000 as Weight)
+			.saturating_add((3_590_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
 	fn on_initialize_base(r: u32, ) -> Weight {
-		(70826000 as Weight)
-			.saturating_add((10716000 as Weight).saturating_mul(r as Weight))
-			.saturating_add(DbWeight::get().reads(6 as Weight))
-			.saturating_add(DbWeight::get().reads((2 as Weight).saturating_mul(r as Weight)))
-			.saturating_add(DbWeight::get().writes(5 as Weight))
+		(17_597_000 as Weight)
+			.saturating_add((7_248_000 as Weight).saturating_mul(r as Weight))
+			.saturating_add(DbWeight::get().reads(5 as Weight))
+			.saturating_add(DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn delegate(r: u32, ) -> Weight {
-		(72046000 as Weight)
-			.saturating_add((7837000 as Weight).saturating_mul(r as Weight))
+		(93_916_000 as Weight)
+			.saturating_add((10_794_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(4 as Weight))
 			.saturating_add(DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 			.saturating_add(DbWeight::get().writes(4 as Weight))
 			.saturating_add(DbWeight::get().writes((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn undelegate(r: u32, ) -> Weight {
-		(41028000 as Weight)
-			.saturating_add((7810000 as Weight).saturating_mul(r as Weight))
+		(47_855_000 as Weight)
+			.saturating_add((10_805_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().reads((1 as Weight).saturating_mul(r as Weight)))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 			.saturating_add(DbWeight::get().writes((1 as Weight).saturating_mul(r as Weight)))
 	}
 	fn clear_public_proposals() -> Weight {
-		(3643000 as Weight)
+		(4_864_000 as Weight)
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn note_preimage(b: u32, ) -> Weight {
-		(46629000 as Weight)
-			.saturating_add((4000 as Weight).saturating_mul(b as Weight))
+		(66_754_000 as Weight)
+			.saturating_add((4_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(DbWeight::get().reads(1 as Weight))
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn note_imminent_preimage(b: u32, ) -> Weight {
-		(31147000 as Weight)
-			.saturating_add((3000 as Weight).saturating_mul(b as Weight))
+		(44_664_000 as Weight)
+			.saturating_add((3_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(DbWeight::get().reads(1 as Weight))
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn reap_preimage(b: u32, ) -> Weight {
-		(42848000 as Weight)
-			.saturating_add((3000 as Weight).saturating_mul(b as Weight))
+		(59_968_000 as Weight)
+			.saturating_add((3_000 as Weight).saturating_mul(b as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(1 as Weight))
 	}
 	fn unlock_remove(r: u32, ) -> Weight {
-		(45333000 as Weight)
-			.saturating_add((171000 as Weight).saturating_mul(r as Weight))
+		(58_573_000 as Weight)
+			.saturating_add((131_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(3 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn unlock_set(r: u32, ) -> Weight {
-		(44424000 as Weight)
-			.saturating_add((291000 as Weight).saturating_mul(r as Weight))
+		(53_831_000 as Weight)
+			.saturating_add((324_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(3 as Weight))
 			.saturating_add(DbWeight::get().writes(3 as Weight))
 	}
 	fn remove_vote(r: u32, ) -> Weight {
-		(28250000 as Weight)
-			.saturating_add((283000 as Weight).saturating_mul(r as Weight))
+		(31_846_000 as Weight)
+			.saturating_add((327_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
 	fn remove_other_vote(r: u32, ) -> Weight {
-		(28250000 as Weight)
-			.saturating_add((283000 as Weight).saturating_mul(r as Weight))
+		(31_880_000 as Weight)
+			.saturating_add((222_000 as Weight).saturating_mul(r as Weight))
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
diff --git a/frame/democracy/src/lib.rs b/frame/democracy/src/lib.rs
index 9ed732d3234ea..884106a63b321 100644
--- a/frame/democracy/src/lib.rs
+++ b/frame/democracy/src/lib.rs
@@ -155,7 +155,7 @@
 use sp_std::prelude::*;
 use sp_runtime::{
 	DispatchResult, DispatchError, RuntimeDebug,
-	traits::{Zero, Hash, Dispatchable, Saturating},
+	traits::{Zero, Hash, Dispatchable, Saturating, Bounded},
 };
 use codec::{Encode, Decode, Input};
 use frame_support::{
@@ -208,12 +208,14 @@ pub trait WeightInfo {
 	fn vote_new(r: u32, ) -> Weight;
 	fn vote_existing(r: u32, ) -> Weight;
 	fn emergency_cancel() -> Weight;
+	fn blacklist(p: u32, ) -> Weight;
 	fn external_propose(v: u32, ) -> Weight;
 	fn external_propose_majority() -> Weight;
 	fn external_propose_default() -> Weight;
 	fn fast_track() -> Weight;
 	fn veto_external(v: u32, ) -> Weight;
 	fn cancel_referendum() -> Weight;
+	fn cancel_proposal(p: u32, ) -> Weight;
 	fn cancel_queued(r: u32, ) -> Weight;
 	fn on_initialize_base(r: u32, ) -> Weight;
 	fn delegate(r: u32, ) -> Weight;
@@ -285,6 +287,12 @@ pub trait Trait: frame_system::Trait + Sized {
 	/// Origin from which any referendum may be cancelled in an emergency.
 	type CancellationOrigin: EnsureOrigin<Self::Origin>;
 
+	/// Origin from which proposals may be blacklisted.
+	type BlacklistOrigin: EnsureOrigin<Self::Origin>;
+
+	/// Origin from which a proposal may be cancelled and its backers slashed.
+	type CancelProposalOrigin: EnsureOrigin<Self::Origin>;
+
 	/// Origin for anyone able to veto proposals.
 	///
 	/// # Warning
@@ -319,6 +327,9 @@ pub trait Trait: frame_system::Trait + Sized {
 
 	/// Weight information for extrinsics in this pallet.
 	type WeightInfo: WeightInfo;
+
+	/// The maximum number of public proposals that can exist at any time.
+	type MaxProposals: Get<u32>;
 }
 
 #[derive(Clone, Encode, Decode, RuntimeDebug)]
@@ -414,8 +425,7 @@ decl_storage! {
 
 		/// A record of who vetoed what. Maps proposal hash to a possible existent block number
 		/// (until when it may not be resubmitted) and who vetoed it.
-		pub Blacklist get(fn blacklist):
-			map hasher(identity) T::Hash => Option<(T::BlockNumber, Vec<T::AccountId>)>;
+		pub Blacklist: map hasher(identity) T::Hash => Option<(T::BlockNumber, Vec<T::AccountId>)>;
 
 		/// Record of all proposals that have been subject to emergency cancellation.
 		pub Cancellations: map hasher(identity) T::Hash => bool;
@@ -472,6 +482,8 @@ decl_event! {
 		PreimageReaped(Hash, AccountId, Balance, AccountId),
 		/// An \[account\] has been unlocked successfully.
 		Unlocked(AccountId),
+		/// A proposal \[hash\] has been blacklisted permanently.
+		Blacklisted(Hash),
 	}
 }
 
@@ -544,6 +556,10 @@ decl_error! {
 		WrongUpperBound,
 		/// Maximum number of votes reached.
 		MaxVotesReached,
+		/// The provided witness data is wrong.
+		InvalidWitness,
+		/// Maximum number of proposals reached.
+		TooManyProposals,
 	}
 }
 
@@ -591,19 +607,28 @@ decl_module! {
 		///
 		/// Emits `Proposed`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`
-		/// - Db reads: `PublicPropCount`, `PublicProps`
-		/// - Db writes: `PublicPropCount`, `PublicProps`, `DepositOf`
-		/// # </weight>
+		/// Weight: `O(p)`
 		#[weight = T::WeightInfo::propose()]
-		fn propose(origin, proposal_hash: T::Hash, #[compact] value: BalanceOf<T>) {
+		fn propose(origin,
+			proposal_hash: T::Hash,
+			#[compact] value: BalanceOf<T>,
+		) {
 			let who = ensure_signed(origin)?;
 			ensure!(value >= T::MinimumDeposit::get(), Error::<T>::ValueLow);
 
-			T::Currency::reserve(&who, value)?;
-
 			let index = Self::public_prop_count();
+			let real_prop_count = PublicProps::<T>::decode_len().unwrap_or(0) as u32;
+			let max_proposals = T::MaxProposals::get();
+			ensure!(real_prop_count < max_proposals, Error::<T>::TooManyProposals);
+
+			if let Some((until, _)) = <Blacklist<T>>::get(proposal_hash) {
+				ensure!(
+					<frame_system::Module<T>>::block_number() >= until,
+					Error::<T>::ProposalBlacklisted,
+				);
+			}
+
+			T::Currency::reserve(&who, value)?;
 			PublicPropCount::put(index + 1);
 			<DepositOf<T>>::insert(index, (&[&who][..], value));
 
@@ -621,11 +646,7 @@ decl_module! {
 		/// - `seconds_upper_bound`: an upper bound on the current number of seconds on this
 		///   proposal. Extrinsic is weighted according to this value with no refund.
 		///
-		/// # <weight>
-		/// - Complexity: `O(S)` where S is the number of seconds a proposal already has.
-		/// - Db reads: `DepositOf`
-		/// - Db writes: `DepositOf`
-		/// # </weight>
+		/// Weight: `O(S)` where S is the number of seconds a proposal already has.
 		#[weight = T::WeightInfo::second(*seconds_upper_bound)]
 		fn second(origin, #[compact] proposal: PropIndex, #[compact] seconds_upper_bound: u32) {
 			let who = ensure_signed(origin)?;
@@ -648,12 +669,7 @@ decl_module! {
 		/// - `ref_index`: The index of the referendum to vote for.
 		/// - `vote`: The vote configuration.
 		///
-		/// # <weight>
-		/// - Complexity: `O(R)` where R is the number of referendums the voter has voted on.
-		///   weight is charged as if maximum votes.
-		/// - Db reads: `ReferendumInfoOf`, `VotingOf`, `balances locks`
-		/// - Db writes: `ReferendumInfoOf`, `VotingOf`, `balances locks`
-		/// # </weight>
+		/// Weight: `O(R)` where R is the number of referendums the voter has voted on.
 		#[weight = T::WeightInfo::vote_new(T::MaxVotes::get())
 			.max(T::WeightInfo::vote_existing(T::MaxVotes::get()))]
 		fn vote(origin,
@@ -671,11 +687,7 @@ decl_module! {
 		///
 		/// -`ref_index`: The index of the referendum to cancel.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`.
-		/// - Db reads: `ReferendumInfoOf`, `Cancellations`
-		/// - Db writes: `ReferendumInfoOf`, `Cancellations`
-		/// # </weight>
+		/// Weight: `O(1)`.
 		#[weight = (T::WeightInfo::emergency_cancel(), DispatchClass::Operational)]
 		fn emergency_cancel(origin, ref_index: ReferendumIndex) {
 			T::CancellationOrigin::ensure_origin(origin)?;
@@ -695,12 +707,8 @@ decl_module! {
 		///
 		/// - `proposal_hash`: The preimage hash of the proposal.
 		///
-		/// # <weight>
-		/// - Complexity `O(V)` with V number of vetoers in the blacklist of proposal.
+		/// Weight: `O(V)` with V number of vetoers in the blacklist of proposal.
 		///   Decoding vec of length V. Charged as maximum
-		/// - Db reads: `NextExternal`, `Blacklist`
-		/// - Db writes: `NextExternal`
-		/// # </weight>
 		#[weight = T::WeightInfo::external_propose(MAX_VETOERS)]
 		fn external_propose(origin, proposal_hash: T::Hash) {
 			T::ExternalOrigin::ensure_origin(origin)?;
@@ -724,10 +732,7 @@ decl_module! {
 		/// Unlike `external_propose`, blacklisting has no effect on this and it may replace a
 		/// pre-scheduled `external_propose` call.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`
-		/// - Db write: `NextExternal`
-		/// # </weight>
+		/// Weight: `O(1)`
 		#[weight = T::WeightInfo::external_propose_majority()]
 		fn external_propose_majority(origin, proposal_hash: T::Hash) {
 			T::ExternalMajorityOrigin::ensure_origin(origin)?;
@@ -744,10 +749,7 @@ decl_module! {
 		/// Unlike `external_propose`, blacklisting has no effect on this and it may replace a
 		/// pre-scheduled `external_propose` call.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`
-		/// - Db write: `NextExternal`
-		/// # </weight>
+		/// Weight: `O(1)`
 		#[weight = T::WeightInfo::external_propose_default()]
 		fn external_propose_default(origin, proposal_hash: T::Hash) {
 			T::ExternalDefaultOrigin::ensure_origin(origin)?;
@@ -768,12 +770,7 @@ decl_module! {
 		///
 		/// Emits `Started`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`
-		/// - Db reads: `NextExternal`, `ReferendumCount`
-		/// - Db writes: `NextExternal`, `ReferendumCount`, `ReferendumInfoOf`
-		/// - Base Weight: 30.1 µs
-		/// # </weight>
+		/// Weight: `O(1)`
 		#[weight = T::WeightInfo::fast_track()]
 		fn fast_track(origin,
 			proposal_hash: T::Hash,
@@ -818,12 +815,7 @@ decl_module! {
 		///
 		/// Emits `Vetoed`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(V + log(V))` where V is number of `existing vetoers`
-		///   Performs a binary search on `existing_vetoers` which should not be very large.
-		/// - Db reads: `NextExternal`, `Blacklist`
-		/// - Db writes: `NextExternal`, `Blacklist`
-		/// # </weight>
+		/// Weight: `O(V + log(V))` where V is number of `existing vetoers`
 		#[weight = T::WeightInfo::veto_external(MAX_VETOERS)]
 		fn veto_external(origin, proposal_hash: T::Hash) {
 			let who = T::VetoOrigin::ensure_origin(origin)?;
@@ -854,10 +846,7 @@ decl_module! {
 		///
 		/// - `ref_index`: The index of the referendum to cancel.
 		///
-		/// # <weight>
-		/// - Complexity: `O(1)`.
-		/// - Db writes: `ReferendumInfoOf`
-		/// # </weight>
+		/// # Weight: `O(1)`.
 		#[weight = T::WeightInfo::cancel_referendum()]
 		fn cancel_referendum(origin, #[compact] ref_index: ReferendumIndex) {
 			ensure_root(origin)?;
@@ -870,11 +859,7 @@ decl_module! {
 		///
 		/// - `which`: The index of the referendum to cancel.
 		///
-		/// # <weight>
-		/// - `O(D)` where `D` is the items in the dispatch queue. Weighted as `D = 10`.
-		/// - Db reads: `scheduler lookup`, scheduler agenda`
-		/// - Db writes: `scheduler lookup`, scheduler agenda`
-		/// # </weight>
+		/// Weight: `O(D)` where `D` is the items in the dispatch queue. Weighted as `D = 10`.
 		#[weight = (T::WeightInfo::cancel_queued(10), DispatchClass::Operational)]
 		fn cancel_queued(origin, which: ReferendumIndex) {
 			ensure_root(origin)?;
@@ -908,16 +893,10 @@ decl_module! {
 		///
 		/// Emits `Delegated`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(R)` where R is the number of referendums the voter delegating to has
+		/// Weight: `O(R)` where R is the number of referendums the voter delegating to has
 		///   voted on. Weight is charged as if maximum votes.
-		/// - Db reads: 3*`VotingOf`, `origin account locks`
-		/// - Db writes: 3*`VotingOf`, `origin account locks`
-		/// - Db reads per votes: `ReferendumInfoOf`
-		/// - Db writes per votes: `ReferendumInfoOf`
 		// NOTE: weight must cover an incorrect voting of origin with max votes, this is ensure
 		// because a valid delegation cover decoding a direct voting with max votes.
-		/// # </weight>
 		#[weight = T::WeightInfo::delegate(T::MaxVotes::get())]
 		pub fn delegate(
 			origin,
@@ -941,16 +920,10 @@ decl_module! {
 		///
 		/// Emits `Undelegated`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(R)` where R is the number of referendums the voter delegating to has
+		/// Weight: `O(R)` where R is the number of referendums the voter delegating to has
 		///   voted on. Weight is charged as if maximum votes.
-		/// - Db reads: 2*`VotingOf`
-		/// - Db writes: 2*`VotingOf`
-		/// - Db reads per votes: `ReferendumInfoOf`
-		/// - Db writes per votes: `ReferendumInfoOf`
 		// NOTE: weight must cover an incorrect voting of origin with max votes, this is ensure
 		// because a valid delegation cover decoding a direct voting with max votes.
-		/// # </weight>
 		#[weight = T::WeightInfo::undelegate(T::MaxVotes::get().into())]
 		fn undelegate(origin) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
@@ -962,10 +935,7 @@ decl_module! {
 		///
 		/// The dispatch origin of this call must be _Root_.
 		///
-		/// # <weight>
-		/// - `O(1)`.
-		/// - Db writes: `PublicProps`
-		/// # </weight>
+		/// Weight: `O(1)`.
 		#[weight = T::WeightInfo::clear_public_proposals()]
 		fn clear_public_proposals(origin) {
 			ensure_root(origin)?;
@@ -981,11 +951,7 @@ decl_module! {
 		///
 		/// Emits `PreimageNoted`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
-		/// - Db reads: `Preimages`
-		/// - Db writes: `Preimages`
-		/// # </weight>
+		/// Weight: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
 		#[weight = T::WeightInfo::note_preimage(encoded_proposal.len() as u32)]
 		fn note_preimage(origin, encoded_proposal: Vec<u8>) {
 			Self::note_preimage_inner(ensure_signed(origin)?, encoded_proposal)?;
@@ -1012,11 +978,7 @@ decl_module! {
 		///
 		/// Emits `PreimageNoted`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
-		/// - Db reads: `Preimages`
-		/// - Db writes: `Preimages`
-		/// # </weight>
+		/// Weight: `O(E)` with E size of `encoded_proposal` (protected by a required deposit).
 		#[weight = T::WeightInfo::note_imminent_preimage(encoded_proposal.len() as u32)]
 		fn note_imminent_preimage(origin, encoded_proposal: Vec<u8>) -> DispatchResultWithPostInfo {
 			Self::note_imminent_preimage_inner(ensure_signed(origin)?, encoded_proposal)?;
@@ -1052,11 +1014,7 @@ decl_module! {
 		///
 		/// Emits `PreimageReaped`.
 		///
-		/// # <weight>
-		/// - Complexity: `O(D)` where D is length of proposal.
-		/// - Db reads: `Preimages`, provider account data
-		/// - Db writes: `Preimages` provider account data
-		/// # </weight>
+		/// Weight: `O(D)` where D is length of proposal.
 		#[weight = T::WeightInfo::reap_preimage(*proposal_len_upper_bound)]
 		fn reap_preimage(origin, proposal_hash: T::Hash, #[compact] proposal_len_upper_bound: u32) {
 			let who = ensure_signed(origin)?;
@@ -1090,11 +1048,7 @@ decl_module! {
 		///
 		/// - `target`: The account to remove the lock on.
 		///
-		/// # <weight>
-		/// - Complexity `O(R)` with R number of vote of target.
-		/// - Db reads: `VotingOf`, `balances locks`, `target account`
-		/// - Db writes: `VotingOf`, `balances locks`, `target account`
-		/// # </weight>
+		/// Weight: `O(R)` with R number of vote of target.
 		#[weight = T::WeightInfo::unlock_set(T::MaxVotes::get())
 			.max(T::WeightInfo::unlock_remove(T::MaxVotes::get()))]
 		fn unlock(origin, target: T::AccountId) {
@@ -1127,12 +1081,8 @@ decl_module! {
 		///
 		/// - `index`: The index of referendum of the vote to be removed.
 		///
-		/// # <weight>
-		/// - `O(R + log R)` where R is the number of referenda that `target` has voted on.
+		/// Weight: `O(R + log R)` where R is the number of referenda that `target` has voted on.
 		///   Weight is calculated for the maximum number of vote.
-		/// - Db reads: `ReferendumInfoOf`, `VotingOf`
-		/// - Db writes: `ReferendumInfoOf`, `VotingOf`
-		/// # </weight>
 		#[weight = T::WeightInfo::remove_vote(T::MaxVotes::get())]
 		fn remove_vote(origin, index: ReferendumIndex) -> DispatchResult {
 			let who = ensure_signed(origin)?;
@@ -1152,12 +1102,8 @@ decl_module! {
 		///   referendum `index`.
 		/// - `index`: The index of referendum of the vote to be removed.
 		///
-		/// # <weight>
-		/// - `O(R + log R)` where R is the number of referenda that `target` has voted on.
+		/// Weight: `O(R + log R)` where R is the number of referenda that `target` has voted on.
 		///   Weight is calculated for the maximum number of vote.
-		/// - Db reads: `ReferendumInfoOf`, `VotingOf`
-		/// - Db writes: `ReferendumInfoOf`, `VotingOf`
-		/// # </weight>
 		#[weight = T::WeightInfo::remove_other_vote(T::MaxVotes::get())]
 		fn remove_other_vote(origin, target: T::AccountId, index: ReferendumIndex) -> DispatchResult {
 			let who = ensure_signed(origin)?;
@@ -1172,6 +1118,80 @@ decl_module! {
 			ensure_root(origin)?;
 			Self::do_enact_proposal(proposal_hash, index)
 		}
+
+		/// Permanently place a proposal into the blacklist. This prevents it from ever being
+		/// proposed again.
+		///
+		/// If called on a queued public or external proposal, then this will result in it being
+		/// removed. If the `ref_index` supplied is an active referendum with the proposal hash,
+		/// then it will be cancelled.
+		///
+		/// The dispatch origin of this call must be `BlacklistOrigin`.
+		///
+		/// - `proposal_hash`: The proposal hash to blacklist permanently.
+		/// - `ref_index`: An ongoing referendum whose hash is `proposal_hash`, which will be
+		/// cancelled.
+		///
+		/// Weight: `O(p)` (though as this is an high-privilege dispatch, we assume it has a
+		///   reasonable value).
+		#[weight = (T::WeightInfo::blacklist(T::MaxProposals::get()), DispatchClass::Operational)]
+		fn blacklist(origin,
+			proposal_hash: T::Hash,
+			maybe_ref_index: Option<ReferendumIndex>,
+		) {
+			T::BlacklistOrigin::ensure_origin(origin)?;
+
+			// Insert the proposal into the blacklist.
+			let permanent = (T::BlockNumber::max_value(), Vec::<T::AccountId>::new());
+			Blacklist::<T>::insert(&proposal_hash, permanent);
+
+			// Remove the queued proposal, if it's there.
+			PublicProps::<T>::mutate(|props| {
+				if let Some(index) = props.iter().position(|p| p.1 == proposal_hash) {
+					let (prop_index, ..) = props.remove(index);
+					if let Some((whos, amount)) = DepositOf::<T>::take(prop_index) {
+						for who in whos.into_iter() {
+							T::Slash::on_unbalanced(T::Currency::slash_reserved(&who, amount).0);
+						}
+					}
+				}
+			});
+
+			// Remove the external queued referendum, if it's there.
+			if matches!(NextExternal::<T>::get(), Some((h, ..)) if h == proposal_hash) {
+				NextExternal::<T>::kill();
+			}
+
+			// Remove the referendum, if it's there.
+			if let Some(ref_index) = maybe_ref_index {
+				if let Ok(status) = Self::referendum_status(ref_index) {
+					if status.proposal_hash == proposal_hash {
+						Self::internal_cancel_referendum(ref_index);
+					}
+				}
+			}
+
+			Self::deposit_event(RawEvent::Blacklisted(proposal_hash));
+		}
+
+		/// Remove a proposal.
+		///
+		/// The dispatch origin of this call must be `CancelProposalOrigin`.
+		///
+		/// - `prop_index`: The index of the proposal to cancel.
+		///
+		/// Weight: `O(p)` where `p = PublicProps::<T>::decode_len()`
+		#[weight = T::WeightInfo::cancel_proposal(T::MaxProposals::get())]
+		fn cancel_proposal(origin, #[compact] prop_index: PropIndex) {
+			T::CancelProposalOrigin::ensure_origin(origin)?;
+
+			PublicProps::<T>::mutate(|props| props.retain(|p| p.0 != prop_index));
+			if let Some((whos, amount)) = DepositOf::<T>::take(prop_index) {
+				for who in whos.into_iter() {
+					T::Slash::on_unbalanced(T::Currency::slash_reserved(&who, amount).0);
+				}
+			}
+		}
 	}
 }
 
@@ -1608,7 +1628,7 @@ impl<T: Trait> Module<T> {
 	///
 	///
 	/// # <weight>
-	/// If a referendum is launched or maturing take full block weight. Otherwise:
+	/// If a referendum is launched or maturing, this will take full block weight. Otherwise:
 	/// - Complexity: `O(R)` where `R` is the number of unbaked referenda.
 	/// - Db reads: `LastTabledWasExternal`, `NextExternal`, `PublicProps`, `account`,
 	///   `ReferendumCount`, `LowestUnbaked`
diff --git a/frame/democracy/src/tests.rs b/frame/democracy/src/tests.rs
index 7f23eb4cca8ad..bcc7099bb34a4 100644
--- a/frame/democracy/src/tests.rs
+++ b/frame/democracy/src/tests.rs
@@ -49,6 +49,8 @@ const NAY: Vote = Vote { aye: false, conviction: Conviction::None };
 const BIG_AYE: Vote = Vote { aye: true, conviction: Conviction::Locked1x };
 const BIG_NAY: Vote = Vote { aye: false, conviction: Conviction::Locked1x };
 
+const MAX_PROPOSALS: u32 = 100;
+
 impl_outer_origin! {
 	pub enum Origin for Test where system = frame_system {}
 }
@@ -151,6 +153,7 @@ parameter_types! {
 	pub const EnactmentPeriod: u64 = 2;
 	pub const CooloffPeriod: u64 = 2;
 	pub const MaxVotes: u32 = 100;
+	pub const MaxProposals: u32 = MAX_PROPOSALS;
 }
 ord_parameter_types! {
 	pub const One: u64 = 1;
@@ -194,6 +197,8 @@ impl super::Trait for Test {
 	type ExternalDefaultOrigin = EnsureSignedBy<One, u64>;
 	type FastTrackOrigin = EnsureSignedBy<Five, u64>;
 	type CancellationOrigin = EnsureSignedBy<Four, u64>;
+	type BlacklistOrigin = EnsureRoot<u64>;
+	type CancelProposalOrigin = EnsureRoot<u64>;
 	type VetoOrigin = EnsureSignedBy<OneToFive, u64>;
 	type CooloffPeriod = CooloffPeriod;
 	type PreimageByteDeposit = PreimageByteDeposit;
@@ -205,6 +210,7 @@ impl super::Trait for Test {
 	type OperationalPreimageOrigin = EnsureSignedBy<Six, u64>;
 	type PalletsOrigin = OriginCaller;
 	type WeightInfo = ();
+	type MaxProposals = MaxProposals;
 }
 
 pub fn new_test_ext() -> sp_io::TestExternalities {
diff --git a/frame/democracy/src/tests/external_proposing.rs b/frame/democracy/src/tests/external_proposing.rs
index 473eac81cdcb0..3f9be2137906b 100644
--- a/frame/democracy/src/tests/external_proposing.rs
+++ b/frame/democracy/src/tests/external_proposing.rs
@@ -79,6 +79,32 @@ fn veto_external_works() {
 	});
 }
 
+#[test]
+fn external_blacklisting_should_work() {
+	new_test_ext().execute_with(|| {
+		System::set_block_number(0);
+
+		assert_ok!(Democracy::external_propose(
+			Origin::signed(2),
+			set_balance_proposal_hash_and_note(2),
+		));
+
+		let hash = set_balance_proposal_hash(2);
+		assert_ok!(Democracy::blacklist(Origin::root(), hash, None));
+
+		fast_forward_to(2);
+		assert!(Democracy::referendum_status(0).is_err());
+
+		assert_noop!(
+			Democracy::external_propose(
+				Origin::signed(2),
+				set_balance_proposal_hash_and_note(2),
+			),
+			Error::<Test>::ProposalBlacklisted,
+		);
+	});
+}
+
 #[test]
 fn external_referendum_works() {
 	new_test_ext().execute_with(|| {
diff --git a/frame/democracy/src/tests/public_proposals.rs b/frame/democracy/src/tests/public_proposals.rs
index 68ec790baae86..d862aa98e7880 100644
--- a/frame/democracy/src/tests/public_proposals.rs
+++ b/frame/democracy/src/tests/public_proposals.rs
@@ -96,6 +96,45 @@ fn invalid_seconds_upper_bound_should_not_work() {
 	});
 }
 
+#[test]
+fn cancel_proposal_should_work() {
+	new_test_ext().execute_with(|| {
+		System::set_block_number(0);
+		assert_ok!(propose_set_balance_and_note(1, 2, 2));
+		assert_ok!(propose_set_balance_and_note(1, 4, 4));
+		assert_noop!(Democracy::cancel_proposal(Origin::signed(1), 0), BadOrigin);
+		assert_ok!(Democracy::cancel_proposal(Origin::root(), 0));
+		assert_eq!(Democracy::backing_for(0), None);
+		assert_eq!(Democracy::backing_for(1), Some(4));
+	});
+}
+
+#[test]
+fn blacklisting_should_work() {
+	new_test_ext().execute_with(|| {
+		System::set_block_number(0);
+		let hash = set_balance_proposal_hash(2);
+
+		assert_ok!(propose_set_balance_and_note(1, 2, 2));
+		assert_ok!(propose_set_balance_and_note(1, 4, 4));
+
+		assert_noop!(Democracy::blacklist(Origin::signed(1), hash.clone(), None), BadOrigin);
+		assert_ok!(Democracy::blacklist(Origin::root(), hash, None));
+
+		assert_eq!(Democracy::backing_for(0), None);
+		assert_eq!(Democracy::backing_for(1), Some(4));
+
+		assert_noop!(propose_set_balance_and_note(1, 2, 2), Error::<Test>::ProposalBlacklisted);
+
+		fast_forward_to(2);
+
+		let hash = set_balance_proposal_hash(4);
+		assert!(Democracy::referendum_status(0).is_ok());
+		assert_ok!(Democracy::blacklist(Origin::root(), hash, Some(0)));
+		assert!(Democracy::referendum_status(0).is_err());
+	});
+}
+
 #[test]
 fn runners_up_should_come_after() {
 	new_test_ext().execute_with(|| {
diff --git a/frame/staking/src/benchmarking.rs b/frame/staking/src/benchmarking.rs
index afda58db4672f..9cef7be1cec1d 100644
--- a/frame/staking/src/benchmarking.rs
+++ b/frame/staking/src/benchmarking.rs
@@ -23,20 +23,12 @@ use testing_utils::*;
 
 use sp_runtime::traits::One;
 use frame_system::RawOrigin;
-pub use frame_benchmarking::{benchmarks, account, whitelisted_caller};
+pub use frame_benchmarking::{benchmarks, account, whitelisted_caller, whitelist_account};
 const SEED: u32 = 0;
 const MAX_SPANS: u32 = 100;
 const MAX_VALIDATORS: u32 = 1000;
 const MAX_SLASHES: u32 = 1000;
 
-macro_rules! do_whitelist {
-	($acc:ident) => {
-		frame_benchmarking::benchmarking::add_to_whitelist(
-			frame_system::Account::<T>::hashed_key_for(&$acc).into()
-		);
-	}
-}
-
 // Add slashing spans to a user account. Not relevant for actual use, only to benchmark
 // read and write operations.
 fn add_slashing_spans<T: Trait>(who: &T::AccountId, spans: u32) {
@@ -120,7 +112,7 @@ benchmarks! {
 		let controller_lookup: <T::Lookup as StaticLookup>::Source = T::Lookup::unlookup(controller.clone());
 		let reward_destination = RewardDestination::Staked;
 		let amount = T::Currency::minimum_balance() * 10.into();
-		do_whitelist!(stash);
+		whitelist_account!(stash);
 	}: _(RawOrigin::Signed(stash.clone()), controller_lookup, amount, reward_destination)
 	verify {
 		assert!(Bonded::<T>::contains_key(stash));
@@ -132,7 +124,7 @@ benchmarks! {
 		let max_additional = T::Currency::minimum_balance() * 10.into();
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created before")?;
 		let original_bonded: BalanceOf<T> = ledger.active;
-		do_whitelist!(stash);
+		whitelist_account!(stash);
 	}: _(RawOrigin::Signed(stash), max_additional)
 	verify {
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created after")?;
@@ -145,7 +137,7 @@ benchmarks! {
 		let amount = T::Currency::minimum_balance() * 10.into();
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created before")?;
 		let original_bonded: BalanceOf<T> = ledger.active;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller.clone()), amount)
 	verify {
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created after")?;
@@ -164,7 +156,7 @@ benchmarks! {
 		CurrentEra::put(EraIndex::max_value());
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created before")?;
 		let original_total: BalanceOf<T> = ledger.total;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: withdraw_unbonded(RawOrigin::Signed(controller.clone()), s)
 	verify {
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created after")?;
@@ -183,7 +175,7 @@ benchmarks! {
 		CurrentEra::put(EraIndex::max_value());
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created before")?;
 		let original_total: BalanceOf<T> = ledger.total;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: withdraw_unbonded(RawOrigin::Signed(controller.clone()), s)
 	verify {
 		assert!(!Ledger::<T>::contains_key(controller));
@@ -192,7 +184,7 @@ benchmarks! {
 	validate {
 		let (stash, controller) = create_stash_controller::<T>(USER_SEED, 100, Default::default())?;
 		let prefs = ValidatorPrefs::default();
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller), prefs)
 	verify {
 		assert!(Validators::<T>::contains_key(stash));
@@ -203,7 +195,7 @@ benchmarks! {
 		let n in 1 .. MAX_NOMINATIONS as u32;
 		let (stash, controller) = create_stash_controller::<T>(n + 1, 100, Default::default())?;
 		let validators = create_validators::<T>(n, 100)?;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller), validators)
 	verify {
 		assert!(Nominators::<T>::contains_key(stash));
@@ -211,13 +203,13 @@ benchmarks! {
 
 	chill {
 		let (_, controller) = create_stash_controller::<T>(USER_SEED, 100, Default::default())?;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller))
 
 	set_payee {
 		let (stash, controller) = create_stash_controller::<T>(USER_SEED, 100, Default::default())?;
 		assert_eq!(Payee::<T>::get(&stash), RewardDestination::Staked);
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller), RewardDestination::Controller)
 	verify {
 		assert_eq!(Payee::<T>::get(&stash), RewardDestination::Controller);
@@ -227,7 +219,7 @@ benchmarks! {
 		let (stash, _) = create_stash_controller::<T>(USER_SEED, 100, Default::default())?;
 		let new_controller = create_funded_user::<T>("new_controller", USER_SEED, 100);
 		let new_controller_lookup = T::Lookup::unlookup(new_controller.clone());
-		do_whitelist!(stash);
+		whitelist_account!(stash);
 	}: _(RawOrigin::Signed(stash), new_controller_lookup)
 	verify {
 		assert!(Ledger::<T>::contains_key(&new_controller));
@@ -350,7 +342,7 @@ benchmarks! {
 		}
 		Ledger::<T>::insert(controller.clone(), staking_ledger.clone());
 		let original_bonded: BalanceOf<T> = staking_ledger.active;
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller.clone()), (l + 100).into())
 	verify {
 		let ledger = Ledger::<T>::get(&controller).ok_or("ledger not created after")?;
@@ -381,7 +373,7 @@ benchmarks! {
 		let (stash, controller) = create_stash_controller::<T>(0, 100, Default::default())?;
 		add_slashing_spans::<T>(&stash, s);
 		T::Currency::make_free_balance_be(&stash, 0.into());
-		do_whitelist!(controller);
+		whitelist_account!(controller);
 	}: _(RawOrigin::Signed(controller), stash.clone(), s)
 	verify {
 		assert!(!Bonded::<T>::contains_key(&stash));
@@ -516,7 +508,7 @@ benchmarks! {
 
 		let era = <Staking<T>>::current_era().unwrap_or(0);
 		let caller: T::AccountId = account("caller", n, SEED);
-		do_whitelist!(caller);
+		whitelist_account!(caller);
 	}: {
 		let result = <Staking<T>>::submit_election_solution(
 			RawOrigin::Signed(caller.clone()).into(),
@@ -584,7 +576,7 @@ benchmarks! {
 
 		let era = <Staking<T>>::current_era().unwrap_or(0);
 		let caller: T::AccountId = account("caller", n, SEED);
-		do_whitelist!(caller);
+		whitelist_account!(caller);
 
 		// submit a very bad solution on-chain
 		{
@@ -638,7 +630,7 @@ benchmarks! {
 		<EraElectionStatus<T>>::put(ElectionStatus::Open(T::BlockNumber::from(1u32)));
 		let era = <Staking<T>>::current_era().unwrap_or(0);
 		let caller: T::AccountId = account("caller", n, SEED);
-		do_whitelist!(caller);
+		whitelist_account!(caller);
 
 		// submit a seq-phragmen with all the good stuff on chain.
 		{