Musical politician overwhelmed by bridge-player’s tragic day (4,4,5)
I believe the answer is:
west side story
'musical' is the definition.
(I've seen this before)
'politician overwhelmed by bridge-player's tragic day' is the wordplay.
'politician' becomes 'tory' (term for a Conservative Party politician).
'overwhelmed by' is a charade indicator (letters next to each other) (in a down clue, some letters go on top of others).
'bridge player's' becomes 'west's' (name given to one player in the card game bridge).
'tragic day' becomes 'ides' (Julius Caesar was killed on the Ides of March).
'wests'+'ides'='westsides'
'tory' put after 'westsides' is 'WEST SIDE STORY'.
(Other definitions for west side story that I've seen before include "Bernstein/Sondheim musical" , "Version of Romeo and Juliet" , "Bernstein musical" , "Jets/Sharks musical" , "1961 film based on Romeo and Juliet, set in a New York slum" .)