What will change under the new criminal justice law

President Trump has signed the First Step Act into law, bringing reform to federal prisons and sentencing laws influenced by the war on drugs.

Why it matters: In an era of extreme partisanship, the bill passed with overwhelming bipartisan support in both the Senate and the House. The new law will send thousands of inmates home immediately, and opens up the possibility for thousands more to reduce their sentences.

The new law will:

• Send up to 4,000 prisoners home by increasing the amount of time inmates can cut off of their sentences due to good behavior.
• Allow inmates to serve time in house arrest or halfway homes instead of prison cells, with exceptions for high-risk inmates.
• Require that prisoners be placed within 500 miles of family.
• Outlaw shackling during childbirth.
• Mandate the provision of sanitary napkins and tampons to female inmates.
• Reduce the mandatory penalty from life to 25 years for a third conviction of certain drug offenses, and from 25 to 15 years for a second conviction.
• Prohibit the doubling up, or "stacking," of mandatory sentences for certain gun and drug offenses.
• Give judges more discretion in giving less than the mandatory minimum for certain low-level crimes.
• Make the 2010 Fair Sentencing Act retroactive, which changed sentencing guidelines to treat offenses involving crack and powder cocaine equally. This could impact nearly 2,600 federal inmates, according to the Marshall Project.

The big picture: This law will only impact the 180,789 people incarcerated in federal prisons, but many of the changes reflect reforms already implemented in some states. The act's passage could also set the stage for more reform at the state and local level.