US writer’s time with American elected politician (5)
I believe the answer is:
twain
'us writer's' is the definition.
(author Mark Twain)
'time with american elected politician' is the wordplay.
'time' becomes 't' (abbreviation).
'with' is a charade indicator (letters next to each other).
'american' becomes 'wa' (I can't justify this - if you can you should give a lot more credence to this answer).
'elected politician' becomes 'in' (in can mean elected or in power).
't'+'wa'+'in'='TWAIN'
(Other definitions for twain that I've seen before include "Mark --, American author" , "Tom Sawyer author, d. 1910" , "Pen name of Samuel Langhorne Clemens, d. 1910)" , "A pen-name" , "Old couple" .)