Louisa Catherine Adams, John Quincy Adams’s wife, had gimlet eyes, a satirist’s wit, and a sharp pencil. To read her letters and diaries is to see the early Republic in vivid color. There is Aaron Burr, who would startle the noisy Senate into silence with “the little hammer in his graceful little hand.” There is John Randolph, of Roanoke, who “was to Congress what Shakespeare’s Fools were to a Court.” There is the wife of the Secretary of War, who clucks about her chickens back in Maine. Martin Van Buren is thinly disguised as “Lord Vandyke Maneuvre.” There are the Southern members of Congress, raging against her husband’s efforts as a representative to present petitions for the restriction of slavery in the eighteen-thirties and forties. “If you have ever seen a puppy in fits,” she wrote to her son, “it will give you some idea of the foaming violence of the Scene.”

Slavery appears in her writing, then—but there are very few slaves. The Washington she painted was not entirely the Washington she lived in. You do not see the people who worked at the stores where she shopped, who served wine at the parties where she danced, or who drove the hacks that she hired; nor the slaves who had lived in her father’s house, her sisters’ houses, her friends’ houses, or even her own. It is almost as if they simply weren’t there.

Her silence was not unusual. For decades, the constitutional settlement had made it untouchable where it existed—and so, in a way, it became unremarkable in daily life. Even those in government who opposed the expansion of slavery did not dwell on the slaves in the coffles that clinked on the road past the Capitol, or the slaves who brushed out their clothing each morning at the boarding houses, or the slave traders who frequented Lafayette Tavern, just a few doors down from the Adams home. To read their debates, it could seem as if the question of whether this land would be free or slave mattered only far away.

But slavery was not an abstraction in Washington, and the élite white men and women who lived there—whatever their principles, whatever their views—interacted with slaves almost every day.

“In a moral and religious point of view and even as a gross political inconsistency with all our boasted Institutions, liberty, and so forth,” Louisa wrote to her father-in-law, John Adams, in 1820, during the debate over whether Missouri could enter the Union without restrictions on slavery, “it is so palpable a stain that the veryest dunce can see it and understand it.” Her husband went further. John Quincy Adams was one of only two Presidents in the nation’s first half century not to own—the language of possession is inescapable—slaves; the other was his father, John. (They were also the only two not to come from Virginia.) John Quincy was not an abolitionist, and he was not among the first leaders of the anti-slavery movement. As president, he was quiet on the subject. But as a representative from Massachusetts after his Presidency, John Quincy would fight in Congress to limit slavery, despite threats against his life and the desertion of his allies, and he denounced it until the moment he died. As early as 1820, long before taking a public stand, he privately raised the prospect of a new union founded on the principle of “total abolition.” “A life devoted to it would be nobly spent or sacrificed,” he wrote in his diary.

But real life, as ever, was more complicated. The census records for that same year, 1820, show a female slave under the age of fourteen living in the Adams residence. The slave was almost certainly not owned by John Quincy. “I abhorred slavery,” he later told an abolitionist, and “did not suffer it in my family,”—and he was not one to lie. But he was human, and he lived in Washington, and, like every politician in Washington—even one whose watchword was integrity—he made compromises. He and Louisa may have rented her from her owners and paid her (and, perhaps, her owner) wages, a common practice in Washington at the time and something we know that the Adamses later did. Or she may have been owned by a member of the extended family who frequently lived with them, sometimes for long periods of time—most likely one of Louisa’s nieces or nephews. Louisa’s father, Joshua Johnson, was a Southerner. The Johnsons, including the families of Louisa’s sisters—her closest friends—owned slaves.

One possibility is that the slave was a young woman named Rachel Clark. In 1816, after Louisa’s niece Mary was orphaned, at the age of ten, Mary inherited stock and “cash, furniture and negroes.” Shortly after, she went to live with John Quincy and Louisa. It is not known what happened to the slaves, but Mary may have brought one with her. In the South, it was common for a wealthy white girl to be “given” a domestic slave about her age; it was thought to cultivate the slave’s loyalty. We know that Mary had a slave named Rachel Clark because in 1828—near the end of John Quincy Adams’s term as President, after Mary had been living with him and Louisa for ten years, including in the White House—Mary set her free. She did it on the same day that she married Louisa and John Quincy’s son.

Neither Louisa nor John Quincy ever mentioned Rachel Clark’s manumission in any extant diary or letter. The only record we have of it is from the clerk who recorded it. In his diary, John Quincy recorded in great detail what else happened that day of the wedding: his walk at daybreak, his sitting for a portrait, his visitors, his tasks, and the name of the twenty or so friends and family who gathered at the White House to witness the marriage. “The servants of the family were likewise all present,” he wrote. He does not say whether “the servants” included Rachel Clark.

Slaves are there, in passing, in faint outline. Occasionally, a quick aside will suggest that there is more to their story with the Adamses, though what that is remains untold.

Take Julia—“an excellent servant,” Louisa wrote. Julia appears to have been a slave whom the Adamses hired. When she was about to be sold by her owner to “a Brute, a Virginia slave holder,” Louisa wrote that she wished she “could raise the sum wanted to release her from her bondage. . . . If I could be put into a way of raising a subscription for this purpose; I should be very happy.” But Louisa was quick to add that she would only give a little money. “I could not appear in the business in any way, but by contributing.”

There is also another Clark. In 1834, Louisa’s younger sister Adelaide—who was also Mary’s stepmother—freed a slave named Jane Clark. Jane Clark later appears in John Quincy’s diary. The Adamses called her Jenny. She “lived sometimes with us,” John Quincy later wrote in his diary. Jane had a son named Joseph, whom Adelaide had sold. When Joseph was wrongfully resold after being promised freedom and taken by his new owner to Arkansas, in 1843, Jane—by then Jane Davies—appealed to John Quincy for help. “Can I not possibly do something for this man?” John Quincy wrote in his diary. The note of anguish in John Quincy’s voice is clear. There may also be a note of regret.

In recent years—and even in recent months—there has been a movement to recover a fuller understanding of the complexity and the incredible extent of slavery in the early Republic. It is in the scholarship of historians dating back to the nineteen-sixties, which has exerted an increasingly visible influence on popular history; it is in the spirit of Black Lives Matter; it is a subtext in the student protests on campuses where slaveholders’ names appear on the sides of buildings; it is part of the decision to replace Andrew Jackson with Harriet Tubman on the front of the twenty-dollar bill. In mid-April, the Times ran a feature on the parallel efforts of a Georgetown University alumnus and a university group working to reckon with the ownership of slaves and the sale of two hundred and seventy-two men, women, and children by the institution in 1838.

It is commonplace to say that the past is not like the present and that historical figures should be considered in their own context. Still, it can be startling to realize just how embedded in the complex and brutal economy of slavery everyone in Washington was.

There were those, of course, who profited from it, and those who dedicated their lives to abolishing it. Then there were a few like John Quincy, who eventually made brave and sincere efforts to remake the world, but who silently saw it every day, even though he may have been troubled as he looked away. And there were others like Louisa, who questioned slavery and denounced it but feared its undoing. If the moment had come for “the calamity which sooner or later must end the strife,” she did not want her husband to be the agent, “the scourge through which this great event is to be atchieved,” even as she supported and championed his efforts.

She was a keen observer of the times but also limited by them. She was convinced that slavery would end only with war, and she had seen enough of the devastating effects of war in Europe to fear it at home. Like all but a small number of white Americans, she was too prejudiced to see that slavery itself was predicated on and perpetuated by violence and brutality. She could not see that there was already a kind of civil war under way. Americans were fighting Americans—sometimes even their own relatives, though the white paternity of many slaves was never acknowledged. That unacknowledged civil war was waged on fields and inside houses throughout the South and West, fought against bodies and minds, with nooses and lashes—only the violence was almost all on one side.

There was then, as there is now, an idealized vision of a grand new experiment in freedom. But, in their lives, there were messy, sometimes intolerable contradictions. The past is like the present, in one important way: it isn’t always what we want it to be.

Louisa Thomas is a contributing writer for newyorker.com. She is the author of “Louisa: The Extraordinary Life of Mrs. Adams,” a biography of the wife of John Quincy Adams.