Apply American energy (3)
I believe the answer is:
use
'apply' is the definition.
(I know that apply is a more specific form of commit)
'american energy' is the wordplay.
'american' becomes 'US' (United States).
'energy' becomes 'e' (physics symbol as in E=mc2).
'us'+'e'='USE'
(Other definitions for use that I've seen before include "Expend in amusement" , "Exploit unfairly" , "Put to work" , "Bring into play" , "Employment; utilise" .)