HARRISBURG, Pa. (AP) — A Pennsylvania state court on Thursday struck down a law designed to make it easier for gun owners and organizations like the National Rifle Association to challenge local firearms ordinances in court.

The Commonwealth Court said the procedure the Republican-controlled Legislature used to enact the law in the final days of last year’s session violated the state constitution. The ruling came after dozens of municipalities had already repealed their gun laws.

Under the law, gun owners no longer had to show they were harmed by a local ordinance to challenge it, and it let “membership organizations” like the NRA sue on behalf of any Pennsylvania member. The law also allowed successful challengers to seek damages.

The NRA’s lobbying arm had called the measure “the strongest firearms pre-emption statute in the country.”

Five Democratic legislators and the cities of Philadelphia, Pittsburgh and Lancaster sued to block the law, saying it was passed improperly. The GOP defendants included House Speaker Mike Turzai and then-Gov. Tom Corbett, who lost his bid for re-election last year.

Thursday’s ruling sends “a very strong message to the General Assembly that the old way of doing business just isn’t acceptable anymore,” said Mark McDonald, press secretary to Philadelphia Mayor Michael Nutter. “The law requires and the public expects transparency, deliberation and public debate.”

Said Pittsburgh Mayor Bill Peduto: “I’m overjoyed that the court system is joining us in standing up for citizens and public safety instead of special rights for the gun lobby.”

CeaseFirePA, a statewide group that works to stop gun violence, declared the ruling “a huge victory against the NRA.”

Pennsylvania, which has a strong tradition of hunting and gun ownership, has long prohibited its municipalities from enforcing firearms ordinances that regulate the ownership, possession, transfer or transportation of guns or ammunition. Gun-rights groups complained that scores of municipalities ignored the 40-year-old prohibition by approving their own gun restrictions.

The NRA seized on the new state law, which took effect in January, to challenge gun measures in Philadelphia, Pittsburgh and Lancaster. None of those lawsuits has been decided, and judges presiding over them may delay rulings until the state Supreme Court takes up the issue of the law’s constitutionality.

“We respectfully disagree with the court’s ruling. We think the standard they applied creates an unworkable legislative process,” said Jonathan Goldstein, an attorney for the NRA.

The Senate Republican caucus anticipates appealing the decision, said spokeswoman Jenn Kocher.

It “undermines a lawful act of the legislative branch, which was thoroughly debated, passed both houses and was signed by the governor. In so doing, the court allowed those opposed to the legislation to achieve via the courts what they could not achieve through the legislative process,” Kocher said.

About 50 Pennsylvania municipalities have already repealed, or were in the process of repealing, their gun laws, according to Joshua Prince, an attorney for four pro-gun groups, who had put the municipalities on notice that they would face legal action unless they rescinded their firearms ordinances.

Sen. Daylin Leach, one of the Democratic lawmakers who joined in the challenge of the law, said the municipalities that repealed their gun ordinances because of the law can now restore them.

Prince said that would be unwise. He predicted the Supreme Court will ultimately decide whether to keep the new law on the books.

But Reading Mayor Vaughn Spencer, whose city was among those that repealed their gun ordinances under threat of legal action by Prince, said Thursday he would push to restore them if the Commonwealth Court ruling looks like it will stand.

“Obviously, if it’s something we’re able to put back in place, I’m hoping that council would support that effort because that would be the right thing to do,” he told the Reading Eagle newspaper.

The court’s decision hinged on how the bill was put together last year.

The gun provision was merged with a bill whose intent was to establish criminal penalties for theft of secondary metals, such as wires or cables. The Commonwealth Court judges said that process violated constitutional requirements that bills may not be altered to change their original purpose and must be confined to one subject.