diff --git a/packages/cosmic-swingset/src/chain-main.js b/packages/cosmic-swingset/src/chain-main.js
index fbb6b37ffe2..e0b41526d81 100644
--- a/packages/cosmic-swingset/src/chain-main.js
+++ b/packages/cosmic-swingset/src/chain-main.js
@@ -256,7 +256,9 @@ export default async function main(progname, args, { env, homedir, agcc }) {
       stateDir: stateDBDir,
     });
 
-    const consensusMode = env.DEBUG === undefined;
+    // We want to make it hard for a validator to accidentally disable
+    // consensusMode.
+    const consensusMode = true;
     const s = await launch(
       stateDBDir,
       mailboxStorage,
diff --git a/packages/cosmic-swingset/src/launch-chain.js b/packages/cosmic-swingset/src/launch-chain.js
index 705c626397a..12499ce15c2 100644
--- a/packages/cosmic-swingset/src/launch-chain.js
+++ b/packages/cosmic-swingset/src/launch-chain.js
@@ -146,7 +146,7 @@ export async function launch(
   meterProvider = DEFAULT_METER_PROVIDER,
   slogFile = undefined,
   slogSender,
-  consensusMode = false,
+  consensusMode = true,
 ) {
   console.info('Launching SwingSet kernel');
 
diff --git a/packages/cosmic-swingset/src/sim-chain.js b/packages/cosmic-swingset/src/sim-chain.js
index 36736fccde4..430f57f8f96 100644
--- a/packages/cosmic-swingset/src/sim-chain.js
+++ b/packages/cosmic-swingset/src/sim-chain.js
@@ -91,6 +91,8 @@ export async function connectToFakeChain(basedir, GCI, delay, inbound) {
     stateDir: stateDBdir,
   });
 
+  // We don't want to force a sim chain to use consensus mode.
+  const consensusMode = false;
   const s = await launch(
     stateDBdir,
     mailboxStorage,
@@ -102,6 +104,7 @@ export async function connectToFakeChain(basedir, GCI, delay, inbound) {
     metricsProvider,
     SLOGFILE,
     slogSender,
+    consensusMode,
   );
 
   const { savedHeight, savedActions, savedChainSends } = s;