A federal trial over Oregon’s voter-approved gun control measure is set to open Monday in Portland, marking a critical next step for one of the toughest gun control laws in the nation after months of being tied up in the courts.

The trial, which will be held before a judge and not a jury, will determine whether the law violates the U.S. Constitution.

The protracted legal battle over the law could well last beyond the trial. Whatever the judge decides, the ruling is likely to be appealed, potentially moving all the way up to the U.S. Supreme Court.

Oregon voters in November narrowly passed Measure 114, which requires residents to undergo safety training and a background check to obtain a permit to buy a gun.

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The legislation also bans the sale, transfer or import of gun magazines with more than 10 rounds unless they are owned by law enforcement or a military member or were owned before the measure’s passage. Those who already own high-capacity magazines can only possess them at home or use them at a firing range, in shooting competitions or for hunting as allowed by state law after the measure takes effect.

firearms are displayed

Firearms are displayed at a gun shop in Salem, Oregon, on Feb. 19, 2021. A judge in Portland, Oregon, will hear arguments on June 5, 2023, over the constitutionality of a gun control law that was approved by voters last year. (AP Photo/Andrew Selsky, File)

The Oregon Firearms Federation and a county sheriff filed the federal lawsuit in November, contending it violated the right to bear arms under the Second Amendment of the U.S. Constitution. Democratic Attorney General Ellen Rosenblum and former Democratic Gov. Kate Brown are named as defendants.

It was one of several lawsuits filed over the measure.

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In a separate lawsuit, filed in state court in rural and sparsely populated Harney County in southeastern Oregon, Gun Owners of America Inc., the Gun Owners Foundation and several individual gun owners claimed the law violates the Oregon Constitution.

The judge presiding over that case, Harney County Judge Robert S. Raschio, in December ordered the law to be put on hold. Because the lawsuit challenged Measure 114 under the state constitution and not the U.S. Constitution, it held precedence in the state, legal experts said. A trial is scheduled for September.

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Supporters of the law say it would reduce mass shootings and other forms of guns violence as well as suicides, which the Oregon Health Authority said accounts for 82% of gun deaths in the state.

The measure’s fate is being carefully watched as one of the first new gun restrictions since the U.S. Supreme Court last June struck down a New York law that limited carrying guns outside the home. The high court has allowed the law to remain in force while a lawsuit plays out.