JFK, RFK.
Title 5, 3110 of the United States Code states:
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 RFKs nomination.)
Was a problem. Don't want a repeat.
JFK, RFK. Bad idea then, bad idea now.