Nepotism and the Cabinet
A public official may not appoint, employ, promote, advance, or advocate for appointment, employment, promotion, or advancement, in or to a civilian position in the agency in which he is serving or over which he exercises jurisdiction or control any individual who is a relative of the public official.
This anti-corruption statute is reasonable enough, but the plain language also applies to the President. In other words, John F. Kennedy could not have appointed Robert Kennedy as Attorney General if this provision had existed in 1961. (The statute was enacted in 1967, probably in response to RFK’s nomination.)
I have serious doubts that Section 3110 is constitutional as applied to a President. First, as far as I can tell, this is the only statutory limit on the President’s authority to choose his political appointees. Separation-of-powers would suggest that Congress cannot intrude so bluntly into his discretion to choose close advisors. Second, if the position is subject to Senate confirmation, that represents an adequate check on executive excess. Third, presidents would take a significant political hit if they abused their appointment authority to help out friends and relatives. (BTW, what does relative mean? Any relation? Only a spouse, child, or sibling?)