Maybe it's just because I'm a Virginian, but I think the death of General George Washington was the death knell of the United States - he'd offered to negotiate those early conflicts between Virginia and what was then Maryland at his Mount Vernon estate... arguments got heated, and though both sides denied having been the ones that fired that shot that killed him, a unified America died with him. Once you had a war between Virginia and Maryland, the Articles of Confederation just kind of went out the window.
Things worked out here in Virginia fairly well - the Commonwealth still managed to reach the Rockies, thanks to buying
Mississippi from Louisiana, not that the reach of Nouvelle Orléans ever made it much farther than Petite Roche anyway.
Once Pennsylvania and New York stopped fighting each other, and finally merged into the American Compact, they managed to make a decent job at turning the great lakes into their own Mare Nostrum, whatever bits Virginia didn't take anyway.
New England, like the Brits, always had their naval empire.
I mean, there were also the Carolinas, or the
Maroni up in
Deseret, but they can't all be success stories.
Kind of makes one want to think about what they might have accomplished together.