Trusty system (prison)
The trusty system worked out well for prison officials because they did not have to pay civilian (non-prisoner) guards to control the prisoners.  However, the trusties kept the other prisoners under control through physical abuse, torture, fear, and humiliation.  Finally, in 1974, a federal court ruled that the trusty system, and the whole prison, were violating the United States Constitution by giving out cruel and unusual punishments.  This ruling ordered the trusty system to be shut down.