After years of plunging crime rates, hugely expensive incarceration budgets and troubling racial disparities in criminal punishment, it has become fashionable on the presidential campaign trail to declare the United States' uncommonly high rate of imprisonment unacceptable.
Just don’t press candidates to explain how to significantly change it.
Hillary Clinton began demanding an end to the “era of mass incarceration” almost from the day she launched her campaign. Sen. Bernie Sanders recently made a pledge that would include cutting the prison population by more than one-quarter within four years.
On the Republican side,...