America ahead -- about right to take over (5)
I believe the answer is:
usurp
'take over' is the definition.
('usurp' can be a synonym of 'take over')
'america ahead about' is the wordplay.
'america' becomes 'us' (abbreviation for the United States).
'ahead' becomes 'pru' (I am not sure about this - if you are sure you should believe this answer much more).
'about' is a reversal indicator.
'pru' back-to-front is 'urp'.
'us'+'urp'='USURP'
'right to' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for usurp that I've seen before include "Depose illegally" , "Assume by force" , "Commandeer" , "Appropriate without authority" , "Take (power) by force or illegally" .)