On this day in history, February 19, 1807, Aaron Burr is arrested for treason. Aaron Burr was America's third Vice-President under Thomas Jefferson. He is best-known today for killing Alexander Hamilton in a duel after some private comments Hamilton made disparaging Burr's character were made public and Hamilton refused to retract the statements.
Less known is an incident Burr was involved in after his term as vice-president ended along with his political career due to the Hamilton incident. After his term, Burr went west to the American frontier and purchased land in the newly purchased Louisiana Territory, where he became involved in a scheme to either develop a new state in Louisiana or, more seriously, to conquer part of Mexico, apparently hoping to revive his political career.
This was illegal because Mexico was still a Spanish possession and only the United States government had the authority to make war or negotiate with foreign governments. Burr worked together with US General James Wilkinson who was the US Army Commander at New Orleans and the Governor of the Louisiana Territory. Together they developed their plans and raised a small privately funded army to accomplish their ends. They even negotiated with Great Britain, which considered aiding their plans, but eventually pulled out.
General Wilkinson eventually became nervous that the plans would fail and he could be implicated in a crime. He turned on Burr and wrote to President Thomas Jefferson about Burr's plan and accused him of treason. In addition, some of Jefferson's slave-holding supporters demanded that he do something about Burr because whatever territory Burr ended up controlling would be slave-free, since he was firmly against slavery. They did not want a slave-free territory in the south. Jefferson eventually charged Burr with treason, a charge which didn't exactly fit the crime. Burr tried to escape to Spanish Florida, but was caught at Wakefield in the Mississippi Territory on February 19, 1807.
Burr was tried in a sensational trial in Richmond, Virginia beginning on August 3. He was represented by Edmund Randolph and Luther Martin, both former members of the Continental Congress. The evidence was so flimsy against Burr that four grand juries had to be convened before the prosecution could get an indictment. General Wilkinson, the chief witness for the prosecution, was found to have forged a letter, allegedly from Burr, stating his plans to steal land from Louisiana. This weakened the prosecution's case and left Wilkinson in disgrace.
Chief Justice of the Supreme Court, John Marshall, oversaw the case and was pressured by Thomas Jefferson to make a conviction. Marshall, however, did not find Burr guilty of treason and he was acquitted on September 1. He was then tried on a more reasonable misdemeanor charge, but was acquitted of this charge as well.
After the trial, Burr's hopes of reviving his political career were dead and he fled to Europe. For several years, he attempted to talk various European governments into cooperating with his plans to conquer Mexico, but he was rebuffed by all. Eventually he returned to the United States and resumed his law practice in New York, where he maintained a relatively low profile for the rest of his life.