Burr’s arithmetic was superficially flawless, although not every court proceeding had been a full-fledged trial: he had survived two attempted grand jury investigations in Kentucky, one in Mississippi, and had won two full trials in Virginia. But Burr could not press his double jeopardy objection until a grand jury actually indicted him. The current proceeding before the chief justice was merely a preliminary arraignment. Marshall therefore allowed the government to proceed.

The prosecutors paraded three dozen witnesses through the courtroom, including many of Burr’s adventurers. They described an expedition with a distinctly military character. By the time the expedition had reached the mouth of the Cumberland River, its 100 crew members had acquired weapons such as muskets, bayonets, and tomahawks. They performed drills on their boats. Burr recognized that he was losing ground in the courtroom. “It is impossible to predict when this business may terminate,” he wrote his daughter, “as the chief justice has gradually relaxed from former rules of evidence, and will now hear anything.”

A moment of high drama arose when General Wilkinson—Burr’s chief accuser (and leading accomplice)—took the stand in public for the first time. One observer thought that the stout, florid military man “exhibited the manner of a sergeant under court martial rather than the demeanor of an accusing officer confronted with his culprit.” Wilkinson first addressed the principal documentary evidence, a letter in cipher from Burr, two copies of which had been delivered to Wilkinson by trusted couriers. When he first released the cipher letter publicly, Wilkinson had altered it in subtle yet critical ways to minimize his prior involvement with Burr.

Salivating at the sight of the duplicitous general, the defense lawyers took turns cross-examining him. John Wickham’s hours-long grilling made Wilkinson squirm and decline to answer many questions.

Indeed, Wilkinson was not a credible witness. When the grand jury had heard his secret testimony, they nearly indicted him as part of Burr’s scheme. The grand jury foreman, Congressman John Randolph of Virginia, called Wilkinson “the only man that I ever saw who was from the bark to the very core a villain.” Randolph added that “the mammoth of iniquity escaped—not that any man pretended to think him innocent.”

Despite the fireworks surrounding Wilkinson’s appearance, Marshall refused to sustain the new treason charges. He did find probable cause that Burr had violated the Neutrality Act by planning an invasion of Mexico. After posting bail, Burr walked free, seven months after the marshals first brought him to Richmond. The case was transferred to the federal court in Ohio, where it languished for months and was finally dropped.

Aaron Burr, the fallen angel of America’s founding generation, had escaped the hangman, thwarted the president who hated and feared him, and skirted the evidence of his own misdeeds. It marked a signal achievement by a brilliant lawyer who had utterly failed to realize his dream of creating a new empire on the American continent.


Although ruined, Burr would not slip quietly into oblivion. In 1808 he traveled to Europe, where he spent three years unsuccessfully trying to inveigle Great Britain or France into underwriting a new expedition to liberate Spain’s American colonies—with him at the head. By 1813 he was back in New York, where he practiced law into his late 70s, dying on Staten Island in 1836 at the age of 80.

Burr’s trial had profound implications beyond the fate of the defendant. As former president John Adams wrote during the case, “something must come out on the trial, which will strengthen or weaken our confidence in the general union.” The case framed a central historical irony. Marshall, the last great figure of the aristocratic Federalist Party, shut down a national security prosecution by his tenacious protection of Burr’s rights. Jefferson, the supposed advocate of individual liberty, proclaimed Burr’s guilt publicly and avidly pursued his conviction through deeply flawed prosecutions.

The case proved a landmark, with Marshall’s rulings establishing central principles of our legal system. The writ of habeas corpus survives even when national security is at stake. Prosecutions for treason must meet the exacting requirements set out in the Constitution. And the president is not above the law when it comes to providing evidence for court cases.

One final principle shone through the verbiage of the long courtroom struggle. After the trial was over, Marshall confided that he had found the trial “deplorably serious.” By vigilantly protecting Burr’s rights, the chief justice revealed his view that constitutional rights mean nothing unless they were available to even such a reviled defendant as Aaron Burr in 1807. And the principle that even the most controversial defendants are entitled to a fair trial remains intact today.