America getting behind party filled with resentment is risky (9)
I believe the answer is:
dangerous
'is risky' is the definition.
(similar in meaning)
'america getting behind party filled with resentment' is the wordplay.
'america' becomes 'US' (United States).
'getting behind' means one lot of letters go next to another (some letters go behind others).
'party' becomes 'do' (do is a kind of party).
'filled with' is an insertion indicator.
'resentment' becomes 'anger' (I've seen this in another clue).
'do' enclosing 'anger' is 'dangero'.
'us' put after 'dangero' is 'DANGEROUS'.
(Other definitions for dangerous that I've seen before include "Hairy" , "Hazardous" , "Posing a hazard" , "Harmful, injurious" , "Not safe" .)