Enforcement of the 2016 law that bans possession of high-capacity magazines has been blocked pending the outcome of the lawsuit.

Mark J. Terrill / AP

The Thousand Oaks shooter used a high-capacity magazine that, in 2016, California voters banned anyone in the state from possessing, but implementation of the law has been blocked by a lawsuit brought by the NRA and other gun rights advocates. Authorities say 28-year-old Marine veteran Ian David Long used a Glock 21 .45-caliber handgun with an extended magazine to kill 12 people at the popular Borderline Bar & Grill Wednesday night. Ventura County Sheriff Geoff Dean said Long obtained the gun legally, but did not immediately know where, when, or how Long obtained the high-capacity magazine. He also didn’t know how many rounds were loaded. In 2000, California outlawed the sale or purchase of magazines capable of holding more than 10 rounds, although anyone who already had them could keep them. But that changed in 2016 when 63% of Californians — spurred by the 2015 San Bernardino attack that killed 14 — voted to close the loophole and ban even the possession of higher-capacity magazines. Proposition 63 was pushed hard by Lt. Gov. Gavin Newsom and lawmakers who argued that large-capacity ammunition magazines “significantly increase a shooter’s ability to kill a lot of people in a short amount of time.”

AP A victim is carried from the scene of the shooting Nov. 7, 2018, in Thousand Oaks.

However, implementation of the legislation was quickly opposed by the California Rifle & Pistol Association — the official state association of the National Rifle Association — and five residents who sued, arguing the new rule would violate their Second Amendment rights by restricting their ability to defend themselves against a violent attacker. “In confrontation with a violent attacker, having enough ammunition can be the difference between life and death,” the lawsuit states. Implementation of Prop. 63, which was to go into effect July 1, 2017, was since delayed by a federal court pending a final ruling on the case. And a final pretrial conference for the lawsuit isn’t scheduled until March 11, 2019.

But Newsom, now governor-elect, told reporters Thursday that it was time to enforce laws that voters had approved.

Janie Har / AP California governor-elect Gavin Newsom addresses the shooting and gun control on Nov. 8, 2018.

“So we’ve got to push those through, we’ve got to get out of the courts and we’ve got to implement them,” he said. Democratic Rep. Brad Sherman, who represents the nearby 30th Congressional District, also said on Twitter that “it’s time for California to uphold the will of the voters.”

Officials have confirmed that the #ThousandOaks shooter used a high-capacity magazine that Californians voted to ban in 2016. The @NRA filed a lawsuit to block the law. It's time for California to uphold the will of the voters, enforce the law, and for the country to follow suit.