President Barack Obama commuted the prison sentences of 61 drug offenders on Wednesday, including more than a third serving life sentences, working to give new energy to calls for overhauling the U.S. criminal justice system.

All of the inmates are serving time for drug possession, intent to sell or related crimes. Most are nonviolent offenders, although a few were also charged with firearms violations. Obama’s commutation shortens their sentences, with most of the inmates set to be released on July 28.