President Trump just backed the prison and criminal justice reform bill, the First Step Act. Not only is Trump’s endorsement an exceptional display of bipartisanship in a time of partisan rancor and stagnation, but it’s also a groundbreaking moment for the modern American presidency. Presidents from both parties since the 1980s, from Bill Clinton to Ronald Reagan, contributed to a quadrupling of the American prison population despite violent crime plateauing. For Trump to sign into law what former President Barack Obama never could, free 4,000 people with a single stroke of a pen, and set hundreds of thousands of other prisoners on a course to rehabilitate their lives and potentially leave prison would be nothing short of a miracle.

The First Step Act primarily enacts back-end prison reform, changing how the prison system treats people who are already incarcerated with a view to reducing recidivism. It would create opt-in rehabilitative and vocational programs, which for low-risk prisoners can apply as credits to reduce prison sentences. It also makes a number of long overdue reforms, such as banning the handcuffing of pregnant prisoners (yes, that happens).