How odd that Americans, and not just their presidents, have come to think of their Constitution as something separable from the government it's supposed to constitute. In theory, it should be as binding on rulers as the laws of physics are on engineers who design bridges; in practice, its axioms have become mere options. Of course engineers don't have to take oaths to respect the law of gravity; reality gives them no choice. Politics, as we see, makes all human laws optional for politicians.