False. There is nothing in the Oath to obey the president.  That is the nazi oath. The Oath is to obey lawful orders from the chain of command - including the president, but to defend the Constitution. If there is a legal order from the chain of command, it will be followed, but any illegal orders from anyone in the chain of command, from POTUS to platoon sergeant, that doesn't have to be followed, and if the order violates the Constitution, there is a duty to defend against.