No that was not sarcasm. Proposition A is to increase taxes on a rich minority in order to increase "welfare benefits" for the masses. Constitutional provision B prohibits proposition A from becoming law. Now, constitutional provision B is a protection of a minority against the majority. Constitutional provision B is hardly leftist. And that's not sarcasm!
Wonderfully concise, thanks. Given that particular example, it would not be leftist. Other examples may be given that are. The constitutional proposition in itself may be neutral. The execution of constitutional provisions becomes leftist or rightist depending on the power elite that enforces it.