The story first emerged during the brawling, cutthroat era of American politics that attended the birth of the nation's two-party system at the dawn of the 19th century.

It was a time of savage rhetoric played out in partisan newspapers, of the jailing and clubbings of adversaries, of political disputes sometimes settled with pistols.

The liaison between founding father Thomas Jefferson and his slave mistress, Sally Hemings, linked now through DNA, began as one more brick in the fight.

It has parallels, too, in the current scandal of the president and his paramour. Both Jefferson and President Clinton, scholars point out, became involved with women young enough to be their daughters. Each endangered his career and issued evasive denials.

Jefferson's ordeal began publicly in 1802 with an alcoholic Scottish journalist named James Thomson Callender.

Callender had been forced to flee England after printed attacks on George III. He would wreak in America what Jefferson biographer Fawn M. Brodie called "more mischief than any newspaper man of his age."

Callender initially had been in the camp of Jefferson and what was then known as the Republican party. In 1797, Callender exposed an adulterous affair involving Alexander Hamilton, leader of the opposition Federalist party. Two years later, Callender assailed Federalist President John Adams as a "hideous hermaphroditical character."

But in 1801, after being fined and jailed by the Federalists and hailed as a "martyr" by Republicans, Callender turned his sights on newly elected President Jefferson.

Even though Jefferson had pardoned his Federalist conviction, Callender, armed with the long-rumored Hemings story historians say he may first have heard in jail, demanded that Jefferson pay his $200 fine and appoint him postmaster in Richmond.

Jefferson balked but gave Callender $50. "He intimated that he was in possession of things which he could and would use . . . (and) that he received the 50 D . . . as hush money," Jefferson wrote. "He knows nothing of which I am not willing to declare to the world myself."

The next July, from his post at a new Federalist newspaper, the Richmond Recorder, Callender began to snipe at Jefferson. When Republican editors hit back, Callender, on Sept. 1, 1802, broke the Hemings story.

"It is well known that the man, whom it delighteth the people to honor, keeps and for many years has kept, as his concubine, one of his slaves," he began. "Her name is SALLY. . . . By this wench Sally, our president has had several children."

The story sparked a firestorm. Callender was attacked by Republicans as a "clot-hearted Scot."

Jefferson never responded directly but noted in a letter that "the federalists have opened all their sluices of calumny."

The controversy boiled on for months but gradually died down. The next July, Callender was found dead in the James River -- after trying to bathe while drunk, authorities said.

And the story of Sally Hemings went dormant, according to Annette Gordon-Reed, who last year published a study of the affair. "Whenever there was a controversy and people wanted to hurt Jefferson, they would refer to Sally," she said.

Many scholars, protective of Jefferson, rejected the story. "If Jefferson was wrong, America was wrong," biographer James Parton wrote in 1874.

There remained, though, an undercurrent of belief, said Jefferson scholar Paul Finkelman, of the University of Akron Law School.

In 1873, one of Hemings's children, Madison Hemings, claimed in a small Ohio newspaper that his mother was Jefferson's "concubine." "He's dismissed," Finkelman said, "as this old illiterate black guy who wants to make Jefferson his father."

And the story remained discredited, relegated to footnotes and appendixes. Then, in 1974, Brodie published her "Thomas Jefferson, an Intimate History," which accepts the Hemings story as factual.

Brodie, who died in 1981, "was vilified by Jefferson scholars," Gordon-Reed said. But her work sparked the interest of novelists and filmmakers and ultimately scientists in the Sally Hemings story.

And despite the gulf of two centuries, the journal that is now publishing the findings could not resist comparisons with a modern-day presidential liaison -- that of Clinton with Monica S. Lewinsky.

"Now, with impeccable timing, Jefferson reappears to remind us of a truth that should be self evident," wrote geneticist Eric S. Lander and historian Joseph J. Ellis in the journal Nature. "Our heroes -- and especially presidents -- are not gods or saints, but flesh-and-blood humans, with all of the frailties and imperfections that this entails." Jefferson went on to win a second term by a landslide, the scholars added, and "his abiding position was that his private life was nobody else's business."