diff --git a/consensus/state.go b/consensus/state.go
index 37803a22..69f65b7e 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -219,7 +219,7 @@ func (rs RoundStepType) String() string {
 	case RoundStepCommit:
 		return "RoundStepCommit"
 	default:
-		panic(Fmt("Unknown RoundStep %X", rs))
+		return "RoundStepUnknown" // Cannot panic.
 	}
 }