It is odd that one of the most infamous Americans accused of being a monarchist is most known for killing the first Treasury Secretary Alexander Hamilton in a duel; a man who was himself often accused of being a monarchist in the ranks of the Founding Fathers of the United States. It was on this day in 1807 that Aaron Burr, former U.S. Vice President in the Thomas Jefferson administration, was first indicted by a grand jury for treason concerning allegations of a conspiracy on his part to become the monarch of a new western American monarchy carved out of the territory of New Spain and Louisiana. It is still uncertain how much of the accusations are fact and how much was simply rumor aimed at several extremely unpopular figures but it involved such prominent individuals that it commanded the attention of the nation and the government at the very highest levels.
The alleged conspiracy was as follows; Burr used his position to get General James Wilkinson, commander of the US Army, appointed Governer of the newly acquired Louisiana Territory, a man who had himself been accused of trying to break away Kentucky and Tennessee from the Union. Burr allegedly conspired with the British minister Anthony Merry for money and support in gaining control of Louisiana in return for increased British influence in the region and Royal Navy dominance in the Gulf of Mexico. He did give Burr some money for the enterprise but he was not supported by London and was eventually recalled though Burr promised the plan would go ahead in any event.
Burr also had land grants from Spain for land in Texas which he also spoke of taking control of and while visiting New Orleans he gained the support of some prominent Mexican exiles who wished to rest the region from Spanish control as well as the local Catholic bishop. Reports soon spread that Burr was raising a private army and was planning to take control of a vast but vague region on the western and southwestern frontier over which he would establish his own government and rule as a king or emperor in grand, Napoleonic fashion. However, different people heard different stories. A Spanish official claimed that Burr had approached him as being sympathetic to the cause of Spain in the New World and that his plan was to take control of the United States and that they should support him as the expanding USA was an obvious threat to the security of New Spain. As with the British, the Spanish government refused him support.
Burr established a base on an island in the Ohio River in what is now West Virginia to gather supplies, munitions and troops for his enterprise. When the Governor of Ohio moved against them Burr was forced to relocate south where General Wilkinson was promising to supply him with troops once he reached New Orleans. By this time alarm bells were going off in Washington as voices were raised warning President Jefferson that Aaron Burr was gathering an army to be used against the US government and to provoke war with Spain in order to carve out his own empire. Jefferson alerted the US Congress and orders went out to arrest any armed men marching for the Spanish border.
General Wilkinson, hoping to save himself, turned traitor on Burr and began supplying information on the plot to the President, which he tweaked in order to make himself look innocent and to portray Burr as threatening to overthrow Jefferson's administration rather than looking to take territory from the Spanish. The President finally ordered Burr's arrest and he was forced to flee to Mississippi. However, it did him no good and he was finally captured and taken to Washington DC to stand trial. However, since the plot had never had a chance to fully develop, and the actual intent and target was widely disputed, Burr was acquited of treason but his future in North America was effectively over. He went into exile in Europe and died, heavily in debt in 1836. General Wilkinson had a very stormy career and ruined himself during the War of 1812 with a disastrous invasion of Canada. He also went into exile and died in Mexico in 1825.