diff --git a/src/scripting/decorate/thingdef_exp.cpp b/src/scripting/decorate/thingdef_exp.cpp
index 229c8f1f4..2d69be340 100644
--- a/src/scripting/decorate/thingdef_exp.cpp
+++ b/src/scripting/decorate/thingdef_exp.cpp
@@ -477,9 +477,12 @@ static FxExpression *ParseExpression0 (FScanner &sc, PClassActor *cls)
 			exp = new FxRuntimeStateIndex(ParseExpressionM(sc, cls));
 		}
 		// The parsed expression is of type 'statelabel', but we want a real state here so we must convert it.
-		FArgumentList args;
-		args.Push(exp);
-		exp = new FxFunctionCall(NAME_ResolveState, NAME_None, args, sc);
+		if (!exp->isConstant())
+		{
+			FArgumentList args;
+			args.Push(exp);
+			exp = new FxFunctionCall(NAME_ResolveState, NAME_None, args, sc);
+		}
 		sc.MustGetToken(')');
 		return exp;
 	}