In the early labor movement, unions claimed the right to strike and organize under the Thirteenth Amendment. Professor Jim Pope wants to resurrect this argument, and he argued against historians Bernstein and Moreno, who argue that the Thirteenth Amendment does not support labor rights. Their argument is that collective labor rights operated as white job cartels, which is inconsistent with the racial equality put forth by the Thirteenth Amendment. Professor Pope acknowledged that their argument was historically accurate but unremarkable. Blacks at the time could not exercise labor rights because of a campaign of violence by the KKK. Blacks attempted to organize for a time, but as the KKK gained influence, some white labor leaders despaired that they could not organize blacks for just that reason. One exception was Southern ports, where blacks had some success in organizing. Black unions could collectively scab when white unions struck for discriminatory policies and exert pressure on employers. Another was the Brotherhood of Sleeping Car Porters, which played an important role in the early civil rights movement. Professor Pope argues more broadly that the Thirteenth Amendment sets out a powerful anti-subjugation principle, which, unlike other provisions in the Constitution, cannot easily be turned by elites to their own purposes.