So help me God. (Title 5 U.S. Code 3331, an individual, except the President, elected or appointed to an office of honor or profit in the civil service or uniformed services) ...

Stated more precisely, the Oaths Clause, along with the president’s oath of office prescribed in Article ... oath to require civil servants and military officers not only to swear allegiance ...

The US Senate approved Donald Trump's nominee to for top military officer after the president abruptly fired the previous chairman of the Joint Chiefs of Staff.