Bitter perhaps in congressional elections (3)
I believe the answer is:
ale
'bitter perhaps' is the definition.
'in congressional elections' is the wordplay.
'in' says the answer is hidden in the clue.
'ALE' is hidden in the letters of 'congressional elections'.
(Other definitions for ale that I've seen before include "Sold in 23" , "One beer" , "Type of beer" , "brewing?" , "A drink; sounds like become ill" .)