Waller County, Texas, has had a complicated racial history since the days when it was a part of Mexico. At one of its first settlements, Bernardo Plantation, about 100 slaves grew cotton on  a large farm on the banks of the Brazos. Yet in the years before Texas fought Mexico for its independence, the area became a magnet for free blacks from elsewhere in the South who sought a welcoming home.

The messy, confusing double legacy of that history has persisted to the present, most recently embodied in the death of Sandra Bland in a Waller County jail cell. Bland, a 28-year-old from Chicago, was on a road trip to start a new job at her alma mater, historically-black Prairie View A&M University, when she was pulled over by a state trooper for failing to signal a turn. Somehow, that apparently routine stop escalated and ended with Bland with an arm injury, under arrest for assaulting an officer. She was found dead in her cell three days later, on July 13, of what police say was suicide by asphyxiation. Her family disputes that account, saying she had no inclination to suicide and was upbeat about her new job....

The history is especially painful because Waller County was for a time a beacon of black progress. During Reconstruction, an office of the Freedmen’s Bureau opened in the county seat of Hempstead, and federal troops—including, for a time, some commanded by George Custer—occupied to keep the peace. Not coincidentally, the Ku Klux Klan also set up shop. Nonetheless, Hempstead became a locus of black political activity and hosted the Republican Party’s statewide convention in 1875. In 1876, the predecessor of Prairie View A&M was established, and in the 1880 Census, the county was majority black.

Waller County had among the highest numbers of lynchings in the state between 1877 and 1950.

But the last two decades of the century saw an influx of white immigrants from Eastern Europe, and that dilution of the black vote, along with the end of Reconstruction, reduced blacks to a minority and slashed their political power. After a 1903 law established “white primaries,” African Americans were effectively shut out of politics—such that in a county with some 8,000 black voters, only 144 Republican votes were cast in 1912, according to The Handbook of Texas. Waller County, as Leah Binkovitz notes, had among the highest numbers of lynchings in the state between 1877 and 1950, according to acomprehensive report by the Equal Justice Initiative.

This may seem like distant history, but it set something of a pattern for the county’s race relations through to the present—and as the events of the last year have made clear, a place’s history is often an effective predictor of how it treats its black residents, from St. Louis County to Cuyahoga County. In fact, the disenfranchisement of black voters in Waller County has continued to be a source of contention....