[SSJKarma]

Captain America wanted to have some time for himself and wanted to stop being the captain and the savior of america ! so he gave up the uniform and started to live a life of his own as a normal person, until the government decided to replace him with someone else.

thus US AGENT was born, same uniform different colors everyone thought it was good to have some one like the captain. until US agents way became clear... he was more deadly then the captain would have ever be. not even giving any terrorist another chances, he even killed without even caring for he thought the terrorist only punishment was to die !

fighting his way, at first people thought it was just great to do that, but when you fight in the street and hurt by yourself cause of your weapons civils that hapenned to be there, people started to want captain america back !

Thus seeing this, the captain only thought was, it must stop, this is not the way we want america to be. for he took back his uniform and weared it once more thinking that only he was made to protect this country the way everyone wanted.

a fight started since US Agent didn't want to give the place back as he was the hero now. CAPT won it and took back his throne, never to give it back to US Agent ever again !

but US Agent is still trying to come back to the prime of his days, even now !

so the answer is...
They are not allies, nor enemies !
they are the ying and the yang !
for the captain is more second chances, while the other is more instant punishment !
but both are fighting on behalf of justice !