Before he withdrew his candidacy, The Post reported that Mr. Biden had two proposals in mind: First, establish an enforceable ethics code for the justices; second, subject them to term limits. Each idea presents constitutional issues. It is not clear if life tenure for members of the federal judiciary can be changed through ordinary legislation or would require constitutional amendment. Similarly, any effort by Congress to impose a binding ethics code on the Supreme Court could violate the separation of powers. For now, though, it’s enough to consider reform suggestions on their merits, which are real.