WHEN I WAS ABOUT 20 YEARS OLD, I happened into a shop that sold stereo equipment and noticed something I had never seen before: large stereo headphones. A customer had them on. His face was weird, flooded with what seemed like ecstasy. The salesman noticed me staring. Here, he said, put them on. I did. The music was Wagner's "Magic Fire Music." I was overwhelmed. Hitler was similarly moved by Wagner's music. We have first hand descriptions of how, at the age of 15, he was transported by the overture to "Rienzi." It seemed he loved the music even before he learned that its creator shared his antisemitism. For me, this knowledge of Hitler's love of Wagner and Wagner's hate of Jews infects the music. I cannot hear any of it now without mentally turning my head and peering up to an imaginary box where I see Hitler. It is revolting. It is upsetting. It changes things. Now I have a similar problem with Thomas Jefferson. We have recently learned through DNA testing that Jefferson was probably the father of Sally Hemings's youngest child, a boy, and maybe the father of the other four children as well. Hemings, of course, was one of Jefferson's slaves -- in 1815, he reported owning 102 of them -- as well as being his late wife's half-sister. He took her to Paris when she was 13 and when she returned two years later, she was pregnant. Lest you think it is the discovery that Jefferson was something other than a Rushmorean monument that bothers me, I hasten to say you are wrong. I never thought otherwise. The Hemings Story, first a whisper and now a dead certainty, always made sense to me. She was much like his late wife in appearance, we are told. Besides, this was 18th-century Virginia and slave owners routinely had sexual relations with their slaves. In this regard, Jefferson was just one of the boys. No, what alters Jefferson's image for me is the fact that I have been forced to pay attention to this relationship. The stories, the endless commentaries (of which this is yet another) shoved Hemings from the wings of the Jeffersonian stage to its center. And that humanized her -- not him -- and made me wonder about the nature of the relationship. Just as the music of Wagner turns my head to that imaginary theater box, so do I now have to follow Jefferson as he dons a coat and goes out of the door of Monticello, seeking Hemings. Is that the way it happened? I don't know. Did Jefferson go to Hemings or was she summoned to him? It doesn't matter. What matters is that on account of Hemings I now focus on the connection between the main house, magnificent Monticello, and the squalor of the slave quarters -- not as bad as some, according to contemporary witnesses, but pretty awful nonetheless. This is the very link that Jefferson went to such pains to disguise. He posed as a creature of intellect, above everything -- including lust. He built his house impractically high on a mountain -- above the fields, the slaves and even, on occasion, the rainy weather below. Now, we have Jefferson the slave owner -- and not a reluctant one, either, like George Washington was. This is, though, the same man who wrote the Declaration of Independence, extolled religious liberty and established the University of Virginia -- and those achievements are epic and, it seems, eternal. He was, we have all been told, a man of his times. But I wonder. I do so not just because Jefferson's slave holding is at odds with the sentiments under glass at the National Archives, but because the explanation is too convenient -- too handy an excuse for a way of life that benefited him enormously. Slavery suited Jefferson -- not just Jefferson the planter, but Jefferson the aesthete. Slaves were at the center of Jefferson's world. They made it possible. They built Monticello, cooked its meals and served its tables. They enabled Jefferson to live like the liberal European aristocrats he met in Paris. He was always living beyond his means, always an obsessive shopper. As Garry Wills has pointed out, Jefferson lived like no president before him and few after. When he died, he was deeply in debt. For Jefferson to have freed his slaves, under Virginia's laws, he would have had to provide for them. Not only would he have lost his low-priced servants, but he would have had to cut back on his own expenses. Two of the dominant American isms are sexism and racism: One or the other is employed to explain just about everything. When it comes to Jefferson, though, maybe it's appropriate to exhume Marxism and to talk not just of racial or sexual exploitation, but of exploitation of the good old economic kind. Jefferson was an enormously self- absorbed man, more interested in mankind than in men, and he might have held on to his slaves no matter what their race. Likewise, some people at that time held racist views but abhorred slavery. This is what Sally Hemings has done to Thomas Jefferson: made him harder, meaner, selfish -- an exploiter. His epic achievements are not diminished. But the man, I am sorry to say, certainly is.