A three-judge panel of the U.S. 9th Circuit on Thursday tossed out a challenge to the legality of Washington’s voter-approved background check law for person-to-person gun transfers.

Earlier this month Jeff Even, with the Washington Solicitor General’s Office, told the panel the gun groups behind the lawsuit had “purely abstract and hypothetical” claims and lacked standing to challenge the statute since they had never been prosecuted under the new law. This week the panel agreed.

“Appellants fail to demonstrate a genuine threat of imminent prosecution,” the panel said in a memo, before pointing out the law has seldom been used.

“The two known instances where prosecutors have enforced the law involved a firearm transferred without a background check that was later used as a murder weapon and a firearm stolen from a store and exchanged for drugs,” the court said. “Absent a history of enforcement against conduct like that alleged here, Appellants fail to show a genuine threat of prosecution conferring standing under the law of this Circuit.”

The lawsuit, filed just weeks after the controversial referendum was approved by voters by a nine-point margin, was brought against state Attorney General Bob Ferguson and Washington State Patrol Chief John Batiste by groups to include the Second Amendment Foundation, the Northwest School of Safety and the Firearms Academy of Seattle. Rejected in 2015 by a lower court, the panel heard both sides of the appeal earlier this month in brief oral arguments.

Backers of the challenge said the court ducked its responsibility. “Standing to be able to bring a lawsuit to protect a fundamental enumerated constitutional right should not be dependent on an imminent threat of prosecution,” Alan Gottlieb, SAF founder, told Guns.com Thursday. “The Courts would never apply that standard to the First Amendment. You should not have to go to jail before challenging a law that is unconstitutional. This was just a way not to hear the merits of the case.”

The referendum, I-594, was backed by over $10 million in funds from billionaire philanthropists and gun control organizations but left both vagueness and non-compliance in its wake after it was approved by voters in 2014. This led lawmakers to make a series of modifications to the law earlier this year over lingering concerns.

A similar ballot initiative in Nevada, which passed in 2016, has likewise been sidelined after that state’s attorney general deemed it unenforceable.