When is a constitutional right not a right? When you’re punished for exercising it. If the government arrests or fines you for something you say, everyone recognizes a violation of the First Amendment, even though you had your say. Yet when prosecutors and courts impose massive punishments on criminal defendants for exercising their Sixth Amendment right to trial by jury, it’s considered business as usual—even by the Supreme Court.

In my own practice I’ve seen cases in which defendants declined a plea bargain, were convicted,...