Because the effect of the 13th amendment was not to abolish slavery but rather limit it to those who had been convicted of a crime, black slaves newly freed after the Civil War found themselves "duly convicted" of crimes and in State prisons where they labored without pay. This situation led the Virginia Supreme Court to remark in an 1871 case, Ruffin v. Commonwealth, that prisoners were "slaves of the state." Until the 1930's, most State and Federal prisons were largely self-sufficient, producing most of the goods and food they consumed and even producing for sale a surplus of food and some industrial products. Prison self- sufficiency and excess production for profit, however, largely ended during the mid-1930's when the United States was in the middle of the Depression and both unions and manufacturers complained about competing prison-made products on the open market. Prison labor did not start to become a major issue again until the 1980's. Until then, most prison-produced goods were either for use within the prison system or for sale to other State agencies. Inefficiencies of prison labor are criticized, and the author notes that some proponents of prison slavery attempt to disguise it as a rehabilitation or vocational program designed to give prisoners job skills that can be used after their release. He also addresses economic and political dimensions of the prison labor issue, pointing out the need for prison unionization to protect inmates and the impact of inmate labor on mainstream workers.