In last year’s ruling, the high court said Americans have a constitutional right to carry concealed weapons in public, overturning laws in New York, California and other states that required the gun owner to show a specific and serious need for self-defense. In the 6-3 decision, Justice Clarence Thomas also said any state or federal restriction on firearm possession, sale or use is unconstitutional unless the government can show it was “consistent with this nation’s historical tradition of firearm regulation,” dating as far back as the nation’s founding.

But the California court said the Supreme Court had not rescinded criteria it set in a 2008 ruling, which – while declaring, for the first time, that individuals have a constitutional right to possess handguns at home for self-defense – allowed state and federal governments to outlaw “dangerous and unusual” firearms. That description, the appeals court said, applies to guns like the AR-15.

The ruling, issued Friday, upheld the conviction of a San Jose man, Alex Bocanegra, who drove to the San Joaquin County town of Manteca and fired an AR-15 rifle at the home of a onetime friend who was having a relationship with Bocanegra’s wife.

Bocanegra, convicted of assault, was sentenced to more than seven years in prison, including eight months for possession of an assault weapon. Using language from the Supreme Court’s 2008 ruling, the appeals court said Bocanegra “certainly was not acting as a law-abiding citizen who possessed his AR-15 rifle for lawful purposes.”

Last year’s Supreme Court ruling, however, has been invoked in challenges to other longstanding gun laws. A federal appeals court in New Orleans cited the ruling in declaring unconstitutional a 1994 federal ban on gun possession by anyone subject to domestic-violence restraining orders, stay-away mandates issued by judges against those who have struck or threatened a spouse or partner. The appeals court said such gun bans were not part of U.S. historical tradition dating back to the nation’s founding.

California has had a similar law since 1993. State Attorney General Rob Bonta and his counterparts in 22 other states have urged the Supreme Court to overrule the appeals court, saying the decision threatens both the state laws and the lives of victims of domestic violence.

Other California gun laws have also come under renewed legal attack, including the state’s limit of one gun purchase per month, a requirement that new handgun models “micro-stamp” their cartridges so that police can identify them at crime scenes and, in a lawsuit Monday, a 10-day mandatory waiting period for all firearm purchases.

Assault weapons, prohibited in California since 1989, are defined in state law as semiautomatic firearms that either have a pistol grip or magazines that can hold at least 10 cartridges. Those guns were banned nationwide in 1994 under a law written by California Sen. Dianne Feinstein, but Congress refused to extend the law when it expired in 2004 and has rejected Feinstein’s repeated attempts to renew it. Nine other states have similar laws, and all are being challenged in court.

The National Rifle Association and its allies have steered many of their federal court cases in California to a sympathetic jurist, U.S. District District Judge Roger Benitez of San Diego. In a 2021 ruling declaring portions of the assault weapons ban unconstitutional, Benitez’s opening words were, “Like the Swiss Army knife, the popular AR-15 rifle is a perfect combination of home defense weapon and homeland defense equipment. Good for both home and battle.”

The Ninth U.S. Circuit Court of Appeals immediately put the ruling on hold, and the law remains in effect. But the Supreme Court has returned the case to Benitez for reconsideration under the standards it announced last year.

Last week’s state appeals court ruling, meanwhile, was the first published appellate decision on the assault weapons law and its validity under the Supreme Court’s current standard. Unless overturned on appeal, it will be a binding precedent for all trial courts in the state’s 58 counties.

The ruling’s conclusions are not binding on federal courts – including the Supreme Court, which may have the last word on the issue – but they must defer to the appeals court’s interpretation of the California law.

“It’s precedent that needs to be considered by any judge,” said Billy Clark, litigation attorney for the San Francisco-based Giffords Law Center to Prevent Gun Violence. He said the Supreme Court has recognized that “the Second Amendment is not unlimited. States can continue to use their police power to pass common-sense gun-safety laws, regulating the sale and possession of particularly dangerous weapons.”

“I thought the opinion was quite good,” John Donohue, a Stanford law professor, told The Chronicle. He said the Supreme Court has affirmed that ”weapons of war are not protected,” and, in the words of retired Army Maj. Gen. Paul Eaton, who trained U.S. forces in Iraq, “the AR-15 is accurately called a weapon of war.” 

But C.D. Michel, lawyer for the California Rifle & Pistol Association, the NRA’s state affiliate, said by email that the appeals court ruling was uninformed and legally inconsequential. “Benitez’s decision is all that will matter,” Michel said. 

Reach Bob Egelko: begelko@sfchronicle.com; Twitter: @BobEgelko