While Burr was vice president, he conspired with General James Wilkinson, commander and chief of the United States Army at New Orleans and Governor of the Louisiana Territory, to potentially invade and colonize the Spanish territory west of the Louisiana Territory. The plan was to establish a separate empire—breaking with the United States; crowning Aaron Burr as emperor; and naming New Orleans as the capital.
After leaving office, Aaron Burr traveled to the western frontier to attempt to gain support for his scheme to establish a new empire. Burr successfully persuaded Harman Blennerhassett to join him, convincing Blennerhassett to provide funds as well as to assist with recruiting other reputable locals. Blennerhassett approached John G. Henderson and Alexander Henderson Jr, who possessed both wealth and reputation—both of which would be adventageous in hatching the plot.
Blennerhassett, however, was unaware of the Henderson’s strong ties to the U.S. government and the family’s strong friendship with George Washington. The brothers sent word about the scheme to their father, Alexander Sr, who then informed President Jefferson and James Madison.
“After dinner we walked into the meadow; my brother, Mr. Blennerhassett, and myself. The subject was then renewed… Mr Blennerhassett observed that it was a subject of great importance. He stated the object was the separation of the union; he mentioned characters who were concerned in it; observed that Col. Burr was the head of it; or words to that effect. … In the course of conversation Mr. Blennerhassett observed that New Orleans would be seized.”
— John Glassford Henderson’s Testimony in the Burr-Blennerhassett Conspiracy Trial
The Arrest and Trial of Burr
After attempts to gain support from Great Britain failed, Wilkinson backed out of the plan and reported Burr’s plot to President Jefferson, who ordered Burr’s arrest for treason. The Henderson brothers would testify along with four dozen witnesses before a grand jury in Richmond, Virginia, following Burr’s arrest and indictment for treason. Burr was acquitted on October 20, 1807 and Blennerhassett was never charged for any crimes.