Effect of international legislation harbouring politician (6)
I believe the answer is:
impact
'effect' is the definition.
(I know that impact is a type of effect)
'international legislation harbouring politician' is the wordplay.
'international' becomes 'i' (abbreviation eg in IMF).
'legislation' becomes 'act' (I've seen this in other clues).
'harbouring' indicates putting letters inside.
'politician' becomes 'MP' (Member of Parliament).
'i'+'act'='iact'
'iact' placed around 'mp' is 'IMPACT'.
'of' is the link.
(Other definitions for impact that I've seen before include "Force of blow or collision" , "Forceful contact between two objects" , "Collision - effect" , "Forceful consequence" , "Forceful striking" .)