The most common and most likely answer to this crossword clue is the 5 letter word NIXON
I've seen this crossword clue in The Sunday Telegraph
N
I
X
O
N
More clues leading to the result NIXON
- Reportedly prison's acceptable for disgraced leader
- Nothing working for disgraced politician
- Nothing working for the President?
- In the news: 9-0 to president
- 5 Nothing working for this old bugger!
- Disgraced leader baring all?
- Veto old and new President
- President, disgraced, having more time to spend with family?
- US president with nothing in diary, apparently
- President with nothing doing!
Buddy explains!

The straight part
We know that "US president" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us president = nixon.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.