The condition of being coerced to labor against one’s will. While slavery is a form of involuntary servitude, involuntary servitude has a broader meaning, including the vestiges of slavery, peonage or a coolie labor system, or work forced by the use or threat of physical restraint or injury or through law. The 13th Amendment outlawed involuntary servitude in 1865.
The United States Constitution, What It Says, What It Means, A Hip Pocket Guide