User blog comment:Mmpratt99 deviantart/I Need a Good Original Name For An Alternate United States/@comment-24324608-20150531193643

Republic of America

American Federation

If it's still a British colony...

Dominion of North America

Commonwealth of America

All of those are based off of real life country names, none of which are dictatorships. A lot of the replies here sound like they just threw in a bunch of random government-y words without any care to their actual meaning or common usage.