"In this time of increased political polarization," writes Bill Clinton, "there is one area where we have a genuine chance at bipartisan cooperation: the over-imprisonment of people who did not commit serious crimes."

Clinton makes this observation in a new collection of essays compiled by the Brennan Center for Justice at New York University. He's right on target, and for a significant reason.

Serious folks across the political spectrum are taking a hard look at the facts behind "over-imprisonment." They're seeing what is true, not what ideology tells them should be true. And the harsh verity is inescapable: The current system of criminal justice is badly broken.

Too often these days, politicians in both parties substitute fantasies for facts. Liberals say trade hurts American workers, when the opposite is plainly proven. Conservatives claim immigrants damage the American character, when they have clearly been enriching our culture for over 200 years.

When facts are dismissed, when reality is denied, there is no common language -- no basis for conversation or compromise. The result is paralysis.

That's why the emerging debate over incarceration is so heartening. It's reviving one of the oldest American traditions: pragmatism. Do what works. And change what doesn't.

Clinton has credibility here. He was president in the '90s, when "our communities were under assault" from a vast increase in violent crime, he writes, and he helped impose draconian policies that "acted to address a genuine national crisis."