In a landmark move, the United States Sentencing Commission, a bipartisan agency that sets federal sentencing policy, voted unanimously on Friday to give nearly a quarter of all federal prisoners the chance to reduce their sentences by an average of more than two years.

The commission had already reduced sentencing guideline levels for nonviolent drug traffickers. Friday’s vote made that reduction retroactive for more than 46,000 prisoners sentenced under the old guidelines. Beginning Nov. 1, eligible inmates may ask for a reduction. The commission postponed any releases for a year to give federal judges time to decide in each case whether a reduced sentence would endanger public safety.

The commission’s bold step, which will ease overcrowding in federal prisons, stands in stark relief to the mind-numbing failure of Congress to make meaningful progress on criminal justice reform. At the same time, it is consistent with a healthy trend among state governments that are finding innovative ways of shrinking prison populations while also reducing crime.

In 2013 alone, 35 states passed at least 85 reform-minded bills that created community-based alternatives to prison, helped inmates to re-enter society, and increased the use of data to help judge a person’s risk of re-offending, according to the Vera Institute of Justice.