Aaron Burr served as third vice president of the U.S. under Thomas Jefferson, who dropped him from the ticket after the first term ended in 1805. Two years later, at Jefferson’s insistence, Burr was tried for treason.Though Burr maintained he was getting ready for war with Spain, he was accused of hiring armed men to invade Mexico and lead the West into secession.The main prosecution witness was General James Wilkinson, commander-in-chief of the U.S. Army at New Orleans. Wearing a uniform trimmed in gold braid, complete with sword, he strode into the courtroom in Richmond, Virginia, “swelling like a turkey cock,” in the words of Washington Irving.Wilkinson had often been in touch with Burr about the armed expedition before denouncing him to the president, and he now produced a letter from Burr. It was, however, written in Wilkinson’s own handwriting. The general said that he’d lost the original, and admitted that in his “copy” he’d erased some parts and changed others.I spoke with David Stewart, author of “American Emperor: Aaron Burr’s Challenge to Jefferson’s America,” on the following topics:1. Secession Plan,2. Treason Trial,3. Effects of Acquittal,4. Trapped in Europe,5. Practice of Law.(Lewis Lapham is the founder of Lapham’s Quarterly and the former editor of Harper’s magazine. He hosts “The World in Time”.