During the Civil War, slaves freed themselves by walking to Union lines. What was a trickle in 1861 became a flood by 1864, as thousands of self-emancipated slaves followed Union soldiers. What the pioneering civil rights activist W.E.B. Du Bois called the “general strike” of slaves changed the outcome of the war, forcing a reluctant Lincoln administration to move toward the Emancipation Proclamation and then the 13th Amendment, all while slowing the Confederate war effort by undermining the labor force and thus the economy. Slaves could not have won the war by themselves, but their actions were crucial in deciding the war and creating its moral impact.

The Civil War may have ended chattel slavery, but the 13th Amendment had a fatal flaw, allowing for an exception from free labor for the incarcerated. Almost immediately, states, especially in the South, used this to control black labor. They began rounding up ex-slaves after the war, passing vagrancy laws that allowed the state to sell their labor. Congressional interference during Reconstruction briefly limited this practice, but by the late 19th century, white rule created a huge economic sector based upon unfree black labor, especially in the prison chain gangs at institutions such as Mississippi’s notorious Parchman Farm, symbol of the Jim Crow era’s murderous regime against black people, as well as in contract labor, where private employers worked black prisoners into the grave. Increasingly, prison authorities compelled labor out of nonblack prisoners as well.

The civil rights movement challenged this prison regime, but by no means ended it. In Texas during the 1970s, segregated prison gangs worked under overseers picking cotton for no money. This was modern slavery. In 1978, 1,500 inmates at the Canfield Prison in Ellis, Tex., refused to work in support of a lawsuit (in part against unpaid prison labor) started by a civil rights activist imprisoned in 1972 for inciting a riot during a protest against a white-owned store. They started a prison strike, which spread through the state’s prison system, gained nationwide attention and lasted for two weeks.

As during the current prison strike, the Texas prisoners had few illusions of immediate victories. But in 1980, the Texas prison labor system was ruled unconstitutional, and no longer would they pick cotton under overseers for no money. This was one victory in a centuries-long struggle; yet Texas has continued to exploit its prisoners for poorly paid work.

Just as the public attention of the 1978 strike contributed to that 1980 decision, so might the current prison strike create changes to the current system of prison labor exploitation. That can happen if we make changes to prison labor systems a central demand of our politicians. The strike will continue until Sept. 9, and it is up to us on the outside to make our voices heard in support of these workers.