The hearings were secret, but both protagonists agreed, for their own purposes, that the general had become the main focus of the grand jury hearings. Wilkinson portrayed himself as victim, while Randolph declared, “There was scarcely a variance of opinion amongst us [in the grand jury] as to his guilt.” In fact, most jurors opposed Randolph’s move to arraign Wilkinson, but did vote to indict Burr on a charge of treason on the basis of the general’s testimony and the ciphered letter he produced. And at a later hearing, when Burr’s lawyers called three grand jurors to give evidence intended to demonstrate the general’s untrustworthiness, their accounts strengthened rather than undermined Wilkinson’s standing as a witness.
With Burr bailed out on ten thousand dollars and directed to appear for trial on August 3 on charges of treason, referring to the threat to New Orleans, and high misdemeanor, relating to the attack on Mexico, Wilkinson was released from his ordeal. “Your enemies have filled the public ear with slanders, & your mind with trouble on that account,” the president wrote consolingly from Washington. “The establishment of their guilt will let the world see what they ought to think of their clamors; it will dissipate the doubts of those who doubted for want of knolege [sic], and will place you on higher ground in the public estimate and public confidence. No one is more sensible than myself of the injustice which has been aimed at you.”
THE PROSECUTION BEGAN with William Eaton’s recollected conversations in the winter of 1805–6 with the accused: “Colonel Burr now laid open his project of revolutionizing the territory west of the Allegheny, establishing an independent empire there; New Orleans to be the capital, and he himself to be the chief; organizing a military force on the waters of the Mississippi, and carrying conquest to Mexico.” Eaton was partially supported by Commodore Truxton, who said nothing of secession, but remembered Burr declaring at that time that he “intended to attack Veracruz and Mexico, give liberty to an enslaved world, and establish an independent government in Mexico.”
Secession returned in an affidavit from Colonel George Morgan, founder of New Madrid, and a pioneer settler in the west from the 1780s, who told of Burr’s conversation when he came to stay in the summer of 1806. “After dinner I spoke of our fine country,” the old man testified. “I observed that when I first went there, there was not a single family between the Allegheny mountains and the Ohio; and that by and by we should have congress sitting in this neighborhood or at Pittsburg [sic]. We were allowed to sport these things over a glass of wine: ‘No, never’ said Colonel Burr, ‘for in less than five years you will be totally divided from the Atlantic states.’ The colonel entered into some arguments to prove why it would and must be so.” Before the argument was over, Burr had shocked Morgan further by insisting that “with two hundred men he could drive congress, with the president at its head, into the river Potomac.”
Marshall’s narrow interpretation of what constituted treason, however, pushed the focus of the trial to the events that took place on Blennerhassett’s island in the Ohio River, since it was there that men, arms, and transport were most obviously brought together to “levy war.” Blennerhassett’s gardener, Peter Taylor, offered a vivid account of a conversation with his normally fastidious employer: “He made a sudden pause and said, ‘I will tell you what, Peter, we are going to take Mexico, one of the finest and richest places in the whole world.’ He said that Colonel Burr would be the king of Mexico, and Mrs. Alston, daughter of Colonel Burr, was to be the queen of Mexico whenever Colonel Burr died. He said that Colonel Burr had made fortunes for many in his time, but none for himself; but now he was going to make something for himself.”
The evidence of other young men invited by Blennerhassett to join an undefined adventure in the west— the defense insisted it was merely to settle Burr’s 300,000- acre holding on the Ouachita River— was inconclusive, and in any event while they were on the island, Burr was demonstrably a hundred miles away with Andrew Jackson. On August 20, Burr moved to have the trial ended because the evidence “utterly failed to prove any overt act of war had been committed.” Marshall accepted that the Blennerhassett gathering was not treasonous and refused to hear any evidence relating to events subsequent to it. The prosecution case quickly lapsed, with many witnesses, including Wilkinson, unheard, and when the jurors were called upon to give their verdict, they did so with heavy qualification: “We of the jury say that Aaron Burr is not proved to be guilty under this indictment by any evidence submitted to us. We therefore find him not guilty.”
The wording implied that a fuller hearing might have produced a different verdict, and on the street there was little doubt about Burr’s guilt. Half of those called for jury service in the next trial admitted to entrenched opinions against him, and no one thought him innocent. Jefferson’s fury was unrestrained. Marshall’s handling of the trial, he told Wilkinson, amounted to “a proclamation of impunity to every traitorous combination which may be formed to destroy the Union.”
Unhampered by the judge’s narrow interpretation, Burr’s second trial, beginning in September, for the misdemeanor of planning to attack Mexico, came closer to revealing the true nature of the conspiracy. From its opening debate about the failure of the president to respond to a subpoena duces tecum that required him to produce two letters from the general sent on October 21 and November 12, the defense had Wilkinson in their sights. “We shall prove that he turned traitor to Colonel Burr,” Luther Martin rasped in his brandy-roughened voice, “and violated his engagement with him, by endeavoring to sacrifice him to the government.”
The documents that Wilkinson sent the president on October 21 following Swartwout’s surprise appearance provided the defense with their opening. In his copy and translation of Burr’s ciphered letter, the general was shown to have omitted the opening sentence, “Yours postmarked 13th May is received,” and to have doctored other passages to make them less compromising. In the accompanying letter to Jefferson, Wilkinson had stated, “I am not only uninformed of the prime mover and ultimate objects of the daring enterprize, I am ignorant of the foundation on which it rests, of the means by which it is to be supported,” although Swartwout had told him that it was led by Burr and Mexico was its target. Finally, a postscript on the back of the letter suggested that “some plan be adopted to correct the destination of the associates.” Read together, the inference was clear— that the general was closely associated with the traitor and at least half inclined to collaborate with him, and, as Luther Martin caustically observed, “that he has placed himself in such a situation, he must hang Mr. Burr or be himself eternally detested.”
But in their eagerness to bring down the general, the defense went too far. Martin put Bruff on the stand to give evidence that Wilkinson had privately confessed his involvement in a conspiracy, only to see his story rendered unbelievable when the general produced a letter from Governor Harrison of Indiana warning him, before he even arrived in St. Louis, that Bruff was so unreliable no one in the city trusted him: “The bare idea of his being in your confidence would frighten some of them [the inhabitants] out of their senses.” Nor did Wickham do any better with Thomas Power, who had been brought unwillingly from New Orleans to testify to delivering dollars from Carondelet to Wilkinson. In near hysteria, Power flatly refused as a Spanish citizen to say anything derogatory about the general.