Watch Free Online HD Moviesjoy. For decades, the United States has been fixated on incarceration, building prisons and locking up more and more people. But at what cost, and has it really made a difference? FRONTLINE goes to the epicenter of the raging debate about incarceration in America, focusing on the controversial practice of solitary confinement and on new efforts to reduce the prison population, as officials are rethinking what to do with criminals.