Dodgy American President involved in religious group (7)
I believe the answer is:
suspect
'dodgy' is the definition.
(I've seen this before)
'american president involved in religious group' is the wordplay.
'american' becomes 'us'.
'president' becomes 'p' (common abbreviation eg in VP).
'involved in' is an insertion indicator.
'religious group' becomes 'sect' (I've seen this before).
'us'+'p'='usp'
'usp' going within 'sect' is 'SUSPECT'.
(Other definitions for suspect that I've seen before include "Dodgy" , "Have reason to believe" , "Be ready to believe - one of the usual crowd?" , "one on bail, perhaps" , "Believe (someone) guilty" .)