Summary for new and old readers of the TL.
“We are either a United people, or we are not. If the former, let us, in all matters of general concern act as a nation, which have national objects to promote, and a National character to support--If we are not, let us no longer act a farce by pretending to it.”
- George Washington
"As to the future grandeur of America, and its being a rising empire under one head, whether republican or monarchical, it is one of the idlest and most visionary notions that ever was conceived even by writers of romance. The mutual antipathies and clashing interests of the Americans, their difference of governments, habitudes, and manners, indicate that they will have no centre of union and no common interest. They never can be united into one compact empire under any species of government whatever; a disunited people till the end of time, suspicious and distrustful of each other, they will be divided and subdivided into little commonwealths or principalities, according to natural boundaries, by great bays of the sea, and by vast rivers, lakes, and ridges of mountains."
- Josiah Tucker
(Both OTL quotes).
The Collapse of the Farce
Blunt Summary Style
The POD:
James Madison catches pneumonia on his way back to Virginia in 1783 and dies shortly after.
Madisonless:
Without Madison around, Virginia passes Patrick Henry's "A Bill Establishing a Provision for Teachers of the Christian Religion." It requires people to pay a tax, but they get to say what church they want it to go to, as long as it's a recognized church with a qualified minister. (OTL Madison pulled some tricks to delay the bill and ultimately defeat it, and then managed to pass the Virginia Statute for Religious Freedom).
Baptists are particularly upset by the bill as they see it as violating freedom of religion. Many of them oppose state licensing of preaches on principle and some of them had been put in jail for unlicensed preaching only a few years before. The more western population is also heavily opposed as they have few traditional churches for the tax to go to. If people don't put down where they want the money to go to, it's supposed to got to seminaries in their resident county. But many counties don't have seminaries and sometimes the money goes to the tax collector and then disappears.
Baptists and other groups complain to the Confederal government and their co-religionists in other states, but don't get any relief. This puts a little more stress between Virginia and the Middle States, at a time where the country was barely being held together by the Articles of Confederation, and did not need any more friction.
Without Madison, and with Jefferson in France, the opposition to Patrick Henry is fragmented and less effective. This allows him to stack their delegation to the Constitutional Convention in Philadelphia with anti-fedralists, lead by Richard Henry Lee. A notable exception to anti-federalism amongst the delegates is George Washington, who is too popular for Henry to oppose.
Without Madison's push for a strong central government, and with an anti-federalist Virginia delegation, the Constitutional Convention goes much more poorly than OTL. Unhappy with how the convention is going, and feeling betrayed by his friend George Mason, George Washington takes the opportunity to visit the Society of Cincinnati which was also meeting in Philadelphia. The society is made up of the officers who served the colonial cause in the American Revolution, with membership passed down by primogeniture.
Paranoid fears about the society boil over after seeing Washington go there, and rumors abound that they attend to crown Washington king and overthrow the government. Violence erupts between some of Society of Cincinnati officers and locals oppressed to them. This is the final blow to the Constitutional Convention, as most of the delegates flee Philadelphia carrying rumors of a Washington lead coup with them.
When coup rumors and news of the failed convention reach New York City, where Congress was meeting in an attempt to organize the Northwest territory (and failing due to disagreement on how to fund churches and education in the area), Congress disbanded, and would never again succeed in forming a quorum.
Dissolution
As the Confederation starts to dissolve, states start to think about their best exit strategy. In Britain, Ambassador John Adams, acting on behalf of the Massachusetts Executive Council, negotiates a treaty that advantages Massachusetts, and any other states that would join it and a successor confederation. These states would gain free trade rights with the West Indies and the Maritime colonies of Canada, rights to ship to Britain itself (albeit subject to duties), fishing rights to the Grand Bank off Newfoundland, and official British recognition. The trading and fishing rights were to be denied to other former U.S. States.
In exchange the British would receive favorable trading rights in those states, the boundary of Northern Massachusetts (Maine) settled, and the right to have frigates build for the Royal Navy in Eastern Ports. Massachusetts and the states that would join them would also agree not to interfere with any British operations in the Northwest territory, an easy concession since they basically could not do so anyways.
In 1789 states sent representatives to the Congress of Dover, to either save the Confederation, or as it soon proved: to address the pragmatic issues of ending it. Eventually a grand compromise was reached and an agreement was made on how to divide the debt (largely based on population) and the western territories (largely based on colonial area "sea to seas grants").
Virginia and New York struck out on their own, Vermont was by itself out of necessity (N.H. and N.Y. still holding a claim on their territory), and Rhode Island was in such turmoil that it had not sent representatives to Dover.
The rest of the states formed into regional confederations -
The Unites States of America – A group of middle states that saw themselves as the direct continuation of the Confederation government and came to be known as the 2nd Republic. Members included Pennsylvania, Maryland, Delaware, and New Jersey. They also inherited a part of the Old Northwest Territory. The state of Westsylvania was created to help settle the issue of where Pennsylvania's western border would fall.
New England – A group of Eastern States, consisting originally of Massachusetts, New Hampshire, and Connecticut. They agreed to cede their western claims to the USA for assumption of their share of the debt, a particularly good deal as they had already pledged to Britain not to interfere in the region (as at least the Massachusetts Dover representatives had already known).
Confederate of the Carolinas - A group of Southern states (North and South Carolina and Georgia) that felt they need to stick together to counter Virginia. North Carolina wanted to maintain their western land claim instead of admitting western settlers in as new states. South Carolina did not mind keeping power in the East, and agreed after reaching an agreement with Georgia to receive part of it's claim. Georgia, in dire need of help to face down threats from the Creeks, did not have a strong position from which to bargain.
------------------------------------------------------
So I have conflicting data about the British held forts post war so I changed the map a bit....