About 0.71% of the US population is incarcerated. It's much, much, higher than any other nation. But, still low enough that it doesn't get much attention from voters....even if they turned out in record numbers.

Media attention might make a bigger impact. I'm not sure the general public knows how bad the system is. Even if you're a "punishment" fan, the system is cranking out people that are more likely to commit further crime, since they have little chance to support themselves in a legal way.