By near-unanimous vote, California legislators this week approved a bill that would add a new crime to the state’s longer-than-usual list of charges that can result in the loss of gun rights: misdemeanor hate crimes. Should Governor Jerry Brown sign the bill, the state would become the sixth in the country to implement such a law.

California has a long history of organized hate. Its prison system birthed the Aryan Brotherhood, one of the oldest and largest white supremacist groups in the country. The Southern Poverty Law Center, which tracks hate groups in the United States, has identified 79 in California — more than in any other state.

Like most states, California saw an increase in the number of hate crimes reported in 2016. The rise was concentrated in the state’s large cities, especially Los Angeles. Civil rights groups have blamed the surge on Donald Trump’s racially divisive presidential campaign, though police suggest that another likely explanation could be that more people are reporting incidents. Reports increased 11 percent year-to-year.

There have been several high-profile examples in which firearms were used in hate crimes to kill. In 2012, a known neo-Nazi opened fire at a Sikh temple in Wisconsin, killing six. In June 2015, a committed white supremacist armed with a Glock pistol murdered nine members of a historic African-American congregation in Charleston, South Carolina. This past February, a man in Olathe, Kansas, shot two South Asian patrons of a bar, killing one and wounding a third person who tried to intervene.

However, guns are most often used by perpetrators of hate crimes to terrorize their victims. An analysis by The Trace of hate crimes involving firearms between 2011 and 2013 found that firearms were used in most incidents as a means of intimidation.

Efforts to get guns out of the hands of people convicted of hate crimes picked up after the mass shooting in Charleston. In February 2016, U.S. Representative David Cicilline of Rhode Island, a Democrat, introduced a bill to bar individuals convicted of misdemeanor hate crimes from gun ownership, though it never received a hearing. (The bill sitting on the California governor’s desk mirrors Cicilline’s proposal.) In April of this year, New York State Senator Daniel Squadron put forth his own bill aimed at prohibiting people with low-level hate-crime convictions from getting guns.

If the California bill becomes law, police could have a difficult time enforcing it. Hate-crime reporting is notoriously spotty, and a relatively small share of hate-crime charges result in a guilty verdict. Of the 931 hate crimes logged California in 2016, just 307 were referred for prosecution. The state provided the disposition of just 118 cases of those cases — of which only 51 resulted in a conviction (some defendants charged with hate crimes were convicted of other offenses).

“It’s notoriously difficult” to prosecute hate crimes, former U.S. Attorney Benjamin Wagner told PBS Newshour in January. That’s because the state has to prove defendants’ intent, not just that they committed a particular act.