Inmates walk around a gymnasium where they are housed due to overcrowding at the California Institution for Men state prison in Chino, California in June 2011.

California's Proposition 47 wasn't one of the most followed votes in Tuesday's midterm election, but it could change thousands of lives soon. Under the ballot initiative, dozens of nonviolent property and drug crimes will be reduced from felonies to misdemeanors, potentially freeing tens of thousands of prisoners. Funds that would have otherwise been spent on their incarceration will now be funneled into mental health and drug-treatment programs.

The sentencing-reform measure passed in Tuesday's election with 58 percent of the vote. A large web of donors including California's Catholic bishops, tech-industry giants, and justice-reform groups contributed to its passage; prominent supporters of the measure ranged from Jay-Z to Newt Gingrich.

For the state's beleaguered prison system, Prop 47's changes are long overdue. California prisons and jails have suffered under deplorable conditions for years, resulting in multiple class-action lawsuits from prisoners. By 2011, the U.S. Supreme Court intervened and ordered the state to substantially reduce its prisoner population within two years. Justice Anthony Kennedy, who voted with the majority in Plata v. Brown, summarized the crisis in his majority opinion:

The degree of overcrowding in California’s prisons is exceptional. California’s prisons are designed to house a population just under 80,000, but at the time of the three-judge court’s decision, the population was almost double that. The State’s prisons had operated at around 200% of design capacity for at least 11 years. Prisoners are crammed into spaces neither designed nor intended to house inmates. As many as 200 prisoners may live in a gymnasium, monitored by as few as two or three correctional officers. As many as 54 prisoners may share a single toilet.

These dire conditions took an immense physical and psychological toll on those living under them. Kennedy noted that California's inmate suicide rate in 2006 "was nearly 80% higher than the national average for prison population." To remedy the Eighth Amendment's "systemic violation" in California prisons, as Kennedy phrased it, the Court backed a lower-court plan to reduce the inmate population to 137.5 percent of the system's design occupancy. If the state does not reduce its prison population below this threshold by February 2016, the three-judge panel will appoint a compliance officer to release prisoners early.