By Nicholas K. Geranios / Associated Press

SPOKANE — Sheriffs in more than a dozen Washington counties say they won’t enforce the state’s sweeping new restrictions on semi-automatic rifles until the courts decide whether they are constitutional.

A statewide initiative approved by voters in November raised the minimum age for buying semi-automatic rifles from 18 to 21, required buyers to first pass a firearms safety course and added expanded background checks and gun storage requirements, among other things. It was among the most comprehensive of a string of state-level gun-control measures enacted in the U.S. after last year’s shooting at a Florida high school.

The National Rifle Association and the Second Amendment Foundation have filed a lawsuit in federal court alleging the initiative is unconstitutional. They say its purchasing requirements violate the right to bear arms and stray into the regulation of interstate commerce, which is the province of the federal government.

Sheriffs in 13 mostly rural, conservative counties — Grant, Lincoln, Okanogan, Cowlitz, Douglas, Benton, Pacific, Stevens, Yakima, Wahkiakum, Grays Harbor, Mason and Klickitat — along with the police chief of the small town of Republic, have said they will not enforce the new law until the issues are decided by the courts.

“I swore an oath to defend our citizens and their constitutionally protected rights,” Grant County Sheriff Tom Jones said. “I do not believe the popular vote overrules that.”

Initiative supporters say they are disappointed but noted the sheriffs have no role in enforcing the new restrictions until July 1, when the expanded background checks take effect. The provision brings vetting for semi-automatic rifle and other gun purchases in line with the process for buying pistols.

“The political grandstanding is disheartening,” said Renee Hopkins, chief executive of the Alliance for Gun Responsibility, which pushed the initiative. “If they do not (run the background checks), we will have a huge problem.”

Initiative 1639 was passed by about 60 percent of Washington voters nine months after a gunman opened fire at Florida’s Marjory Stoneman Douglas High School.

The Parkland shooting, which left 17 dead, fueled a shift in the country’s political landscape regarding gun control. Other state-level measures included requiring waiting periods and banning high-capacity magazines. Nine states have approved laws that allow the temporary confiscation of weapons from people deemed a safety risk, bringing the total to 14 nationwide. Several more are likely to follow in the coming months.

At the federal level, for the first time in modern history, gun-control groups outspent the NRA on the 2018 midterm elections. President Donald Trump directed the Justice Department to issue regulations to ban so-called bump stocks. And the new Democratic majority in the House last week held its first hearing on gun control in a decade.

“For far too long, Republicans in Congress have offered moments of silence instead of action in the wake of gun tragedies. That era is over,” Democratic Rep. Jerrold Nadler of New York said as he convened the House Judiciary Committee hearing on Wednesday.

Washington’s initiative targeted semi-automatic assault rifles like the AR-15 used in the Florida shooting and other recent high-profile attacks. Such rifles fire only once for each pull of the trigger but automatically eject and rechamber a new round after each shot.

Grant County’s sheriff said many residents in his part of the state, known for its vast potato farms, are strong supporters of gun rights. They “have a right to have this challenge and appeals process play out before moving forward,” Jones said.

Lincoln County Sheriff Wade Magers noted more than 75 percent of voters in his small county just west of Spokane voted against the initiative. He called the new rules unenforceable.

On the flip side, the sheriff’s offices in King County, which includes Seattle, and Clark County, near Portland, Oregon, have said they will enforce the measure while it is being challenged in court.

Carla Tolle of Kelso, in Cowlitz County, north of Portland, is an initiative supporter whose grandson was shot to death by a friend wielding a shotgun in 2017 in what was ultimately ruled an accidental shooting.

She said she was “shocked, devastated, dumbfounded” to learn Cowlitz County Sheriff Brad Thurman said he will not enforce the stricter gun rules until the legal case is resolved.

“He saw firsthand what happened with an unsecured firearm,” Tolle said. “He saw the effect on both families.”

Spokane County Sheriff Ozzie Knezovich has criticized the initiative while also decrying “grandstanding” sheriffs who decline to enforce it.

Hopkins, of the Alliance for Gun Responsibility, noted only a relatively small number of Washington’s law enforcement leaders are speaking against the measure, while many others support it.

The NRA and the Bellevue-based Second Amendment Foundation sued in U.S. District Court in Seattle in mid-November, saying the initiative violates the Second and 14th amendments of the Constitution as well as gun sellers’ rights under the Commerce Clause.

“This measure will have a chilling effect on the exercise of the constitutional rights of honest citizens while having no impact on criminals, and we will not let it go unchallenged,” Second Amendment Foundation Executive Vice President Alan M. Gottlieb said when the lawsuit was filed.

The lawsuit does not directly challenge the parts of the law pertaining to enhanced background checks or training requirements. However, the groups asked the court to block the entire law pending a determination of whether those provisions can be separated from the parts they are seeking to block: those related to sales to those under 21 and to out-of-state residents.

The state has asked the judge to dismiss the case.