All federal elected officials swear or affirm an oath to support the constitution before they can assume their office. This includes the President, Senators, and Representatives to Congress. For example, here is the oath for Senators:
I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter: So help me God.
Other than the choice of whether to swear or affirm, and some flexibility with the religious parts, this is required. If you break this promise, you are barred from serving in the government.
And then there are those who take this sacrifice for granted, waxing patriotic while salivating for civil war. Claiming they need to destroy the Republic in order to save it in the ultimate betrayal of oaths sworn. Those treacherous snakes can go straight to hell.
— Rep. Peter Meijer (R-MI), in a tweet on Memorial Day.