“It is time to start over,” contends Nancy Isenberg in her iconoclastic “Fallen Founder: The Life of Aaron Burr” (Viking, 544 pages, $29.95). Burr is, of course, infamous for killing Alexander Hamilton in a duel. But historians have also branded Burr a Machiavellian villain who schemed to deny Thomas Jefferson the presidency and most likely committed treason, even though he escaped conviction.

Ms. Isenberg faults historians and biographers for not examining Burr’s papers — although many were lost, thus obscuring the man, she acknowledges. In popular fiction, as well, she notes, Burr has been portrayed as a Gothic villain, highly sexed and unscrupulous, a depiction that derives from the notion expressed, for example, in the “Federalist No. 6,” that “sexual corruption (i.e., seductive women) could be equated with disunion.” Yet, she adds: “It should be clear that Hamilton was not one degree less libidinous than Burr:”

If one reads the newspapers, rather than simply relying on the papers of prominent founders (Hamilton, Jefferson, Adams), it soon becomes clear that sexual satire pervaded politics. The sexualization of Aaron Burr was a means for his opponents to increase their political capital, because the vocabulary to do so was already part of the political scene — not because of Burr’s particular shortcomings.

Gore Vidal made the same point in “Burr” (1973), which Ms. Isenberg briefly mentions, but she does not acknowledge that her book validates Mr. Vidal’s view of a man abiding by important principles the shifty Thomas Jefferson never respected, and living by a code of honor that the scandalmongering Alexander Hamilton could not fathom. Surprisingly, Ms. Isenberg spares not a word for William Carlos Williams’s essay on Burr in “In The American Grain” (1925), which portrays the fallen founder as the very feminist Ms. Isenberg lauds, a man who believed in equal rights for women and practiced his principles in regard to his wife and daughter.

A man with an excellent war record as a staff officer under Washington, attorney general of New York, then a senator, Burr received 30 electoral votes for the presidency in 1796, and tied Jefferson in 1800. Indeed, many electors favored Burr over Jefferson because Burr was a man of both action and principle. He had an admirable reputation in New York —arguing for lower and fairer taxes and various public improvements — that aroused the envy of his rival, Hamilton.

There is no evidence that Burr tried to undermine Jefferson’s election — Burr was quite amenable to serving as Jefferson’s vice president. But Burr did resent Hamilton’s swinging his support to Jefferson in the 1800 election, and the tension between them increased when Hamilton bruited about charges that Burr was a “despicable” man and public servant. Burr demanded that Hamilton explain what he meant, and Hamilton waffled, giving his version of “it depends what you mean by sex.”

Hamilton accepted Burr’s challenge to a duel in New Jersey (where such affairs of honor were legal), even though Hamilton claimed he opposed dueling. Hamilton left word that he would not aim to wound his opponent. Yet, as Ms. Isenberg notes, Hamilton carefully examined the dueling ground, took up various positions to check the sun’s angle, and then put on his spectacles — not exactly the behavior of a man who did not intend to shoot straight. Afterward, Gouverneur Morris, a man who was an excellent “bullshit detector” (to use Hemingway’s term) doubted the veracity of Hamilton’s pre-duel pacifist declaration.

While many condemned Burr — even alleging that he had somehow got the drop on Hamilton (it is not clear who shot first) — many believed he behaved like a gentleman, and his popularity soared in the South. Jefferson had no qualms about dining several times with Burr after the duel, and all charges against Burr were eventually dropped. He returned to Washington, D.C., and presided with dignity and acumen over the impeachment trial of Justice Salmon Chase, drawing praise even from his political enemies.

But Burr’s political career in New York was over. As many Americans did then and since, he went west, hoping to recoup his political power, and earned the admiration of men like Andrew Jackson. Burr’s enemies said he was forming an army to occupy the West and overthrow Jefferson’s administration. Jefferson himself, besotted with suspicion after reading Republican newspapers and relying on doubtful intelligence, rigged a treason prosecution. Already acquitted by three grand juries, Burr faced trial in Richmond, emerging triumphant both in the jury’s verdict and in Chief Justice John Marshall’s judgment. At worst, Burr was guilty of a misdemeanor, for organizing a “filibuster,” a private army intent on liberating Mexico from the Spanish — although no proof was ever produced that such an army actually existed.

As in Mr. Vidal’s novel, Thomas Jefferson emerges in Ms. Isenberg’s biography as a chief executive who never seems to have understood the crucial importance of an independent judiciary or of the rule of law. It was sufficient for him to believe the “will of the people” had turned against Burr and therefore he should be punished. Burr, for his part, submitted himself to the legal process again and again, trusting in the courts. He was a brilliant lawyer, of course, but his exoneration was no mere “technicality.”

I haven’t done justice to Ms. Isenberg’s scrupulous handling of evidence. Her work is profoundly original, and if American historians do not “start over again,” they will be doing their own profession — not to mention the history of their country — an injustice.

crollyson@nysun.com