Aaron Burr had contacted the Spanish minister, Carlos Martínez de Irujo y Tacón, in early 1806 and told him that his plan is not just western succession, but the capture of Washington.

Irujo had written to his masters in Madrid about the coming "dismemberment of the colossal power which was growing at the very gates" of New Spain. (Melton, Buckner, Aaron Burr, Conspiracy to Treason, 2002)

Irujo had given Burr a few thousand dollars to get things started.

The Spanish government in Madrid takes no action.

Jo Daviess, United States District Attorney for Kentucky, writes Jefferson several letters in February and March 1806, warning him of possible conspiratorial activities by Burr.

Jefferson dismisses Daveiss’ accusations against Burr, a Democratic-Republican, as politically motivated.

In the spring of 1806, Burr has his final meeting with Anthony Merry, Britain's representative to the United States in Washington, D.C. from 1803.

In this meeting Merry informs Burr that still no response has been received from London.

Burr tells Merry, "with or without such support it certainly would be made very shortly." (Melton, Buckner, Aaron Burr, Conspiracy to Treason, 2002).

Unfortunately for Merry and Burr, Britain has a new Foreign Secretary, Charles James Fox, who is friendly with America.

Fox finds the request treasonous, and on June 1, 1806, recalls Merry to Britain.

Burr's intention is no doubt to exploit the dissatisfaction of the populace of Louisiana with the purchase.

Daveiss’ July 14 letter to Jefferson states flatly that Burr plans to provoke a rebellion in Spanish-held parts of the West, in order to join them to areas in the Southwest and form an independent nation under his rule.

Similar accusations are published against local Democratic-Republicans in a Frankfort, Kentucky newspaper, Western World.

Jefferson will dismiss Daveiss's accusations against Burr, a Democratic-Republican, as politically motivated.

Later in 1806, Daveiss will bring treason charges against Burr in Kentucky.

The charges will, however, be dismissed thanks to the help of Burr's attorney, Henry Clay.

Following the events in Kentucky, Burr returns to the West later in 1806 to recruit more volunteers for a military expedition down the Mississippi River.

He begins using Blennerhasset Island in the Ohio River to store men and supplies.

The Governor of Ohio grows suspicious of the activity there, and orders the state militia to raid the island and seize all supplies.

Harman Blennerhasset, an Anglo-Irish lawyer and politician, escapes with one boat, and he meets up with Burr at the operation’s headquarters on the Cumberland River.

With a significantly smaller force, the two head down the Ohio to the Mississippi River and New Orleans.

Wilkinson had vowed to supply troops at New Orleans, but, after a near-incident with Spanish forces at Natchitoches, he has concluded that the conspiracy is bound to fail and, rather than providing troops, Wilkinson decides he can best serve his conflicting interests by revealing Burr’s plan to President Jefferson and to his Spanish paymasters.

Jefferson and his cabinet had by mid-1806 begun to take more notice of reports of political instability in the West.

Their suspicions are confirmed when Wilkinson sends the president correspondence which he had received from Burr.

In an attempt to preserve his innocence and career, Wilkinson has edited the letters.

They had been sent to him in cypher, and he has altered the letter to prove both his "innocence" and Burr's guilt.

He warns Jefferson that Burr is “meditating the overthrow of [his] administration” and “conspiring against the State.”

Jefferson alerts Congress of the plan, and orders the arrest of anyone who conspires to attack Spanish territory.

He warns authorities in the West to be aware of suspicious activities.

Jefferson, a political opponent of Burr, issues an order in December for Burr's arrest, declaring that a treasonous plot is underway in the West and calling for the arrest of the perpetrators.

Aaron Burr had continued his excursion down the Mississippi with Harman Blennerhasset and the small army of men that they had recruited in Ohio.

They intend to reach New Orleans, but in Bayou Pierre, thirty miles north of New Orleans, they learn Jefferson had issued an order for Burr's arrest, declaring him a traitor before any indictment.

Burr reads this in a newspaper in the Territory of Orleans on January 10, 1807.

Jefferson's warrant put Federal agents on his trail.

Burr and his men surrender at Bayou Pierre, and Burr is taken into custody.

Charges are brought against him in the Louisiana Territory, but Burr escapes toward Spanish Florida.

Aaron Burr, recaptured on February 13, 1807, had been taken back to Virginia to stand trial.

The case is controversial from the beginning.

Burr's secret correspondence with Anthony Merry and the Marquis of Casa Irujo, the British and Spanish ministers at Washington, is eventually revealed.

He had tried to secure money and to conceal his true design, which was to help Mexico overthrow Spanish power in the Southwest.

Burr had intended to found a dynasty in what would have become former Mexican territory.

This is a misdemeanor, based on the Neutrality Act of 1794, which Congress had passed to block filibuster expeditions against US neighbors, such as those of George Rogers Clark and William Blount.

Jefferson, however, seeks the highest charges against Burr.

In 1807, Burr is brought to trial on a charge of treason before the United States Circuit court at Richmond, Virginia.

His defense lawyers include Edmund Randolph, John Wickham, Luther Martin, and Benjamin Gaines Botts.

Burr had been arraigned four times for treason before a grand jury indicts him.

The only physical evidence presented to the Grand Jury is Wilkinson's so-called letter from Burr, which proposes the idea of stealing land in the Louisiana Purchase.

During the Jury's examination, the court discovers that the letter had been written in Wilkinson's own handwriting.

He says he had made a copy because he had lost the original.

The high misdemeanor charge is dropped when the government is unable to prove that the expedition had been military in nature or directed toward Spanish territory.

The evidence shows only that Burr had planned an illegal attack upon Spanish territory, but he will nevertheless be tried for treason.