Resolved by the House of Representatives {the Senate concurring}, That it is the sense of the Congress that the following Code of Ethics should be adhered to by all Government employees, including officeholders.

CODE OF ETHICS FOR GOVERNMENT SERVICE

Any person in Government service should:

1. Put loyalty to the highest moral principals and to country above loyalty to Government persons, party, or department.

2. Uphold the Constitution, laws, and legal regulations of the United States and of all governments therein and never be a party to their evasion.

3. Give a full day's labor for a full day's pay; giving to the performance of his duties his earnest effort and best thought.

4. Seek to find and employ more efficient and economical ways of getting tasks accomplished.

5. Never discriminate unfairly by the dispensing of special favors or privileges to anyone, whether for remuneration or not; and never accept for himself or his family, favors or benefits under circumstances which might be construed by reasonable persons as influencing the performance of his governmental duties.

6. Make no private promises of any kind binding upon the duties of office, since a Government employee has no private word which can be binding on public duty.

7. Engage in no business with the Government, either directly or indirectly which is inconsistent with the conscientious performance of his governmental duties.

8. Never use any information coming to him confidentially in the performance of governmental duties as a means for making private profit.

9. Expose corruption wherever discovered.

10. Uphold these principles, ever conscious that public office is a public trust.

[Source: U.S. House of Representatives Ethics Committee]

What happened? See Humanist Manifesto II of 1973

Oath of office

U.S. Code TITLE 5 PART III Subpart B CHAPTER 33  SUBCHAPTER II § 3331

An individual, except the President, elected or appointed to an office of honor or profit in the civil service or uniformed services, shall take the following oath: “I, AB, 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.” 

Failure to do so is TREASON

"Patriotism means to stand by the country. It does not mean to stand by the President or any other public official save exactly to the degree in which he himself stands by the country. ... Every man who parrots the cry of “stand by the President” without adding the proviso “so far as he serves the Republic” takes an attitude as essentially unmanly as that of any Stuart royalist who championed the doctrine that the King could do no wrong. No self-respecting and intelligent free man could take such an attitude." -- Theodore Roosevelt (1858-1919) 26th US President Source: Works, vol. 21, pp. 316, 321