About lost power keeping America prepared (7)
I believe the answer is:
readied
'prepared' is the definition.
(I've seen this before)
'about lost power keeping america' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'lost power' becomes 'died' (I've seen this in another clue).
'keeping' indicates putting letters inside.
'america' becomes 'a' (common abbreviation - e.g. in organisation names).
're'+'died'='redied'
'redied' enclosing 'a' is 'READIED'.
(Another definition for readied that I've seen is " Made fit ot prepared for action".)