The American president is merely the “first servant”. Unlike a monarchy, the “sovereign” is the people, or arguably the states (equivalent, in theory to King Charles in the United Kingdom). The president is the chief civil servant and the chief general. There is no logic is arguing the a servant (i.e. the president) is immune from prosecution if he willfully disobeys orders from his master (i.e. the people, as expressed by law).
Note that in halacha, a king’s servants who disobey the king have no immunities from prosecution.