Originalism is usually defended as a theory of interpretation. This Article presents a different view. Originalism ought to be defended, if at all, not based on normative goals or abstract philosophy, but as a positive theory of American legal practice, and particularly of our rules for legal change. One basic assumption of legal systems is that the law, whatever it is, stays the same until it\u27s lawfully changed. Originalism begins this process with an origin, a Founding. Whatever rules we had when the Constitution was adopted, we still have today -- unless something happened that was authorized to change them, under the rules as they stood at the time. We require claims of constitutional change to provide this kind of historical account...