In 1857, the chief justice of the United States, Roger Brooke Taney, declared in his infamous Dred Scott v. Sandford opinion that since the nation’s founding, African Americans — whether free or enslaved — had “had no rights which the white man was bound to respect.” Taney’s opinion was not only inflammatory but based on bad history. It ignored the rights that some Black people had exercised in some states as far back as the Revolution, including the right to vote. More damning, Taney’s words denied what he knew from his own legal practice: Black Americans used the legal system to fight for freedom. And sometimes, they won.

In his gripping new book, “A Question of Freedom: The Families Who Challenged Slavery From the Nation’s Founding to the Civil War,” historian William G. Thomas III provides a profound and prodigiously researched rebuttal to Taney’s lie and to the conventional story that Black people fought for their freedom before the Civil War primarily by risking nighttime escapes or perilous rendezvous with the Underground Railroad. Thomas, a professor of history at the University of Nebraska, describes the legal efforts of a number of African American families who lived in Maryland and D.C. from the colonial period through the Civil War. Thomas shows how families bolstered their claims of freedom through documents, oral histories and accounts of their free ancestors’ arrival in America.

Thomas paints rich multigenerational portraits of families who used their histories in the legal process and won freedom in suit after suit. “Slaves sued slaveholders in every court available to them and in every jurisdiction they could reach from the very beginning of the United States,” he writes.

The key to most of the cases was ancestry — specifically, on the mother’s side. In general, the status of a mother dictated her children’s status as free or enslaved. The female line of descent was therefore crucial to proving that one was a free person. If a petitioner in a freedom suit could demonstrate that she was descended from a free woman, she would be deemed free.

Many enslaved members of a family named Butler were therefore able to win their freedom by proving their descent from Eleanor “Irish Nell” Butler, who had arrived in Maryland as an indentured servant in 1681 and subsequently married an enslaved man. A wave of suits by the Butler family against their putative owners swept the Maryland courts in the 1790s. “In case after case the defendants simply conceded the matter,” Thomas writes. Annapolis juries “awarded the Butlers not only their freedom but also hundreds of pounds of tobacco in damages, lawyer’s fees, and court costs.” Other families, such as the Queens and the Mahoneys, traced their ancestry to a female forbear who was considered non-White but who had spent time in England before arriving in Maryland. They, too, won many of their suits.

Thomas convincingly demonstrates the degree to which courts in Maryland and Washington took seriously these petitioners’ claims. It was not mere legal theater when judges appointed commissioners to carry out months of fact-finding, including traveling to obtain witness depositions. Defendants showed up in court. Juries of property-owning White men, many of them enslavers, found in the petitioners’ favor. Judges did not simply order summary judgment. Petitioners and defendants alike paid huge sums to retain lawyers, among them leaders of the Washington bar such as Philip Barton Key, his nephew Francis Scott Key, and future Supreme Court justices Samuel Chase and Gabriel Duvall.

But not every petition was successful, even when the claim was based on evidence that another court had already found sufficient for freedom. In the 1813 case of Queen v. Hepburn, the Supreme Court held that testimony about the status of petitioner Mina Queen’s ancestor Mary Queen was inadmissible hearsay, despite the fact that the same testimony had been admitted in previous suits brought in different courts by different petitioners. Mina Queen — whose first name was misspelled Mima in printed reports of the case — and her daughter Louisa therefore remained enslaved.

As Thomas notes, many Americans’ increasing commitment to racial subordination and slavery loomed large in the background of the cases. Maryland and D.C. were at the center of this entrenchment. Maryland was a leading supplier in the interstate trade of enslaved people to the cotton South. Washington was not only the seat of the federal government but also the crossroads of the interstate slave trade until Congress abolished such activity in the city in 1850. Coffles of shackled Black men, women and children passed the Capitol daily to auction. A tavern on F Street became notorious as the “Negro Bastille” after an enslaved woman named Ann Williams, who was being forcibly held there by traders, threw herself from the third-floor window in 1815.

Thomas is clear-eyed in his assessment of the forces arrayed against the families. Chief among the institutions resisting their claims was the Catholic Church — specifically, the Jesuit corporation of Maryland. Headquartered at White Marsh plantation in Prince George’s County, the Jesuits were among the largest enslavers in the state. The corporation operated numerous tobacco plantations, kept detailed records of enslaved workers’ productivity and installed as managers priests who lived more like planter grandees than servants of Christ.

Most chilling, perhaps, were the sales. Thomas bookends his narrative with two moments, in 1789 and 1838, when the Jesuits sold off hundreds of enslaved men, women and children to settle the order’s debts and finance its college, which became Georgetown University. Thomas is unsparing in describing the violence that these sales wrought on the families at the center of his study. In the 1838 sale, 272 enslaved people were packed into custom-made brigs, in conditions like those of the Middle Passage, and shipped from the Alexandria, Va., docks to the sugar plantations of Louisiana.

In 2018, Letitia Clark, a physician and a descendant of the Queens, told Thomas that she was shocked to learn about “the cousins that went to Louisiana” nearly 200 years earlier. Her ancestors had remained in Maryland, and some had gained their freedom in court. Those victories in the early 1800s, Clark reflected to Thomas, were a “fifty-year ‘head start’ on freedom.”

As Thomas’s study powerfully demonstrates, that head start was neither an accident nor a gift from White abolitionists. It was the product of antebellum Black American families documenting, petitioning and arguing for their freedom. In countless cases they claimed the republic’s legal system as their own — and won.

A Question of Freedom

The Families Who Challenged Slavery From the Nation’s Founding to the Civil War

By William G. Thomas III

Yale. 418 pp. $35