Between 1783 and 1787 the failed Articles of Confederation were in effect, though it was very unpopular and the Confederation Congress was called in 1787 to solve the problems. In OTL Benjamin Franklin, George Washington, John Adams, Thomas Jefferson, etc, called for a "more perfect union" and the creation of the presidency. However, in this ATL the idea of a stronger union is never realised, this gives radical Monarchists in the congress, (lead by Alexander Hamilton) an excuse to end the republic, arguing that a republic was a failure on all levels for the United States and the young nation would never get anywhere. Slowly but surely the Congress agreed with the Monarchists, first it was John Adams, then Benjamin Franklin and finally George Washington (if reluctantly) agreed with the Monarchists. This left Thomas Jefferson and his die-hard republicans isolated in the congress, with most of the congress on the side of the monarchists, they agreed to have a vote in January to decide the future of the United States.

Scene at the Signing of the Constitution of the United States

Meeting of the Congress of Confederation in late 1787

The Vote

The Vote took place on January 10th, 1788, with the eyes of the nation watching. When the results of the Vote got to the people it was no surprise what the Congress had voted for, a Constitutional Monarchy. Now the next question lied in wait, who was to be crowned monarch? Many people were put into question, though Alexander Hamilton had one of the most startling suggestions: Prince Henry of Prussia, a German prince who had been suggested to him only just over a year before. Without anyone to turn to Congress sent the letter to Prussia offering the American throne to Prince Henry. Thomas Jefferson was outraged by this and is reputed to have said "If we must have a monarch, at least let him be American". But Jefferson's demands fell on deaf ears, Henry accepted the throne as a diplomatic gesture towards Prussia, America now had a King.
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