Orin Kerr nails it in The Significance of the Flubbed Oath:
To my mind, the flubbed oath at today's inaugural teaches one important lesson: The answer to the question, “How many former editors of the Harvard Law Review does it take to administer the Presidential oath properly?” is “More than two.”
He needs to take the oath again. In public. Before he takes any official acts as President. Or the goddamned irredentists will have a field day.