[El Gato]

Do US judges upon their swearing in have to take the oath of office and swear on to protect the Constitution of the USA ? and up hold the US Constitution ?

The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution; but no religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.
Article IV, 3rd paragraph, Constitution for the United States.

So that would be:

YES!

[Prophet in the wilderness]

SO ? this is a test to were their loyalties are ?