when the Civil war ended, there was VERY quickly a shortage of cheap labor in the south....the practice of arresting people..('usually' blacks) on minor offenses and renting out the chain gangs became an important source of revenue...I saw a program that said the at one time, 1/3 of Alabama's budget was financed this way...

this practice lasted much longer than many people realized. I worked in the Civil Rights movement and only recently heard the full story.