Exhaust American power restraining group of countries (3,2)
I believe the answer is:
use up
'exhaust' is the definition.
('use up' can be a synonym of 'exhaust')
'american power restraining group of countries' is the wordplay.
'american' becomes 'us'.
'power' becomes 'p'.
'restraining' indicates putting letters inside.
'group of countries' becomes 'eu'.
'us'+'p'='usp'
'usp' placed around 'eu' is 'USE UP'.
(Other definitions for use up that I've seen before include "Exhaust (resources)" , "Completely consume" , "Expend" , "Finish, exhaust" , "Consume (stocks)" .)