diff --git a/internal/consensus/state.go b/internal/consensus/state.go
index a09527c0e..bc75d7f7b 100644
--- a/internal/consensus/state.go
+++ b/internal/consensus/state.go
@@ -1265,8 +1265,9 @@ func (cs *State) createProposalBlock() (block *types.Block, blockParts *types.Pa
 
 // Enter: `timeoutPropose` after entering Propose.
 // Enter: proposal block and POL is ready.
-// Prevote for LockedBlock if we're locked, or ProposalBlock if valid.
-// Otherwise vote nil.
+// If we received a valid proposal within this round that matches the block we are
+// locked on or matches a block that received a POL in a previous round, prevote
+// for the proposal, otherwise vote nil.
 func (cs *State) enterPrevote(height int64, round int32) {
 	logger := cs.Logger.With("height", height, "round", round)
 
@@ -1296,7 +1297,7 @@ func (cs *State) enterPrevote(height int64, round int32) {
 func (cs *State) defaultDoPrevote(height int64, round int32) {
 	logger := cs.Logger.With("height", height, "round", round)
 
-	// If ProposalBlock is nil, prevote nil.
+	// We did not receive a proposal within this round.
 	if cs.ProposalBlock == nil {
 		logger.Debug("prevote step: ProposalBlock is nil")
 		cs.signAddVote(tmproto.PrevoteType, nil, types.PartSetHeader{})