So here's a great example of how politics makes for awful criminal-justice policy. The Republican candidate for governor in Florida, Rick Scott, says he wants to cut corrections costs by a billion dollars. Great right? Except he wants to do it exclusively by cutting benefits and salaries for prison guards, which is impossible. His other idea is to make inmates grow their own food. They already do grow some food, but they can't grow everything they eat because a bad harvest would mean they'd either have to buy food or starve.
The prison guards' union has responded by accusing Scott of wanting to open the prison doors and release dangerous criminals. This isn't true, but scaring people into thinking Scott wants to open all the prison doors is a more effective argument than running a commercial complaining that he wants to cut your salaries and benefits. Scott doesn't actually want to let anyone out early and isn't particularly interested in reducing the prison population in other ways.
Of course, reducing the number of people in prison is the only way to substantially reduce prison costs. So you have a political candidate who wants to cut prison costs while avoiding the only real way of doing so. Then you have a union that is attacking him for wanting to reduce the prison population, which Scott doesn't want to do. The one thing everyone can agree they shouldn't do is the one thing that would actually work. The state already levies a number of onerous "user fees" on people who go through the criminal-justice system, to the point where you're obligated to pay for a public defender.
In case you're not frustrated yet, Florida has the third largest prison population in the United States, and over the last year, its prison population grew even as it fell overall in the rest of the country.