Answer given by politician originally intended as defence (5)
I believe the answer is:
alibi
'defence' is the definition.
(defence given to police by a suspect)
'answer given by politician originally intended' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'given by' is a charade indicator (letters next to each other).
'politician' becomes 'lib' ().
'originally' indicates taking the first letters.
The first letter of 'intended' is 'i'.
'a'+'lib'+'i'='ALIBI'
'as' is the link.
(Other definitions for alibi that I've seen before include "Defence in court" , "Legal proof of innocence" , "Story confirming innocence" , "Legal defence proving innocence" , "Excuse for failure" .)