Republicans in Indiana’s legislature passed a bill this year intended as the final blow to a long-running lawsuit filed by the city of Gary against gun manufacturers seeking to hold them accountable for local illegal gun sales.

The lawmakers even included language making the bill retroactive to ensure that it would apply to the Gary suit, which was filed nearly a quarter century ago.

On Monday, that effort failed.

Indiana Superior Court Judge John Sedia ruled that while the law barring cities from pursuing lawsuits against the gun industry is constitutional, applying it retroactively would “violate years of vested rights and constitutional guarantees.” It was a rare courtroom setback for makers of firearms in the U.S.

Gary’s case is the last of a generation of civil suits that made similar claims against the gun industry. Attorneys for gun manufacturers and retailers filed for the case to be dismissed based on the new Indiana law, which placed the power to sue solely with the state’s attorney general.

The bill’s backers made no secret that the Gary case was the bill’s target. It included language to make it retroactive to Aug. 27, 1999 — three days before the city filed its lawsuit. But that decision appears to have doomed the industry’s challenge.

The defendants, which include Glock, Smith & Wesson and several other of the nation’s largest gunmakers, argued in a hearing before Sedia last week that the city no longer has the authority to pursue its claims that gunmakers have failed to address an epidemic of illegal gun sales associated with violence in and around Gary.

Philip Bangle, arguing for Gary, countered that, in practical terms, the bill was “special” — specifically aiming at Gary’s suit — and not allowed under the state constitution.

Bangle, an attorney from the Brady center, a nonprofit centered on gun violence prevention, told the judge that similar suits from other towns were not an issue. “There’s none being contemplated; there’s none being threatened; and frankly, looking at what Gary has had to endure these last 25 years, I doubt that any of these bodies would want to,” he added.

In siding with Gary, Sedia cited a 2003 Indiana Supreme Court decision that says a state law cannot be applied retroactively if it violates constitutionally protected rights.

The General Assembly can bar cities from bringing lawsuits against gun manufacturers, but it cannot end this lawsuit, Sedia wrote. “To avoid manifest injustice, the substance of this lawsuit must be taken to its conclusion.”

A representative for the gunmakers said an appeal is coming. “Respectfully, the Superior Court got it wrong,” said Lawrence Keane, senior vice president of the National Shooting Sports Foundation, a trade association representing several of the defendant gunmakers. “The defendants will immediately appeal to the appellate court to correct this error.”

Jody Madeira, a law professor at Indiana University and critic of legislators’ efforts to kill the lawsuit, was thrilled by the judge’s ruling. The main takeaway is clear, she said: State lawmakers “cannot use legislative hoodwinking” to disrupt the lawsuit and Gary will get its day in court.

There was no immediate comment from the Brady center or Gary officials.

For now, the ruling thwarts the latest attempt by the gun industry and its allies to disrupt the case. Filed in 1999, the suit was one of several that decade from major cities against the nation’s most successful gunmakers.

Recognizing the threat the flood of lawsuits posed, the gun industry gathered its political influence to lobby federal lawmakers. They supported federal legislation strong enough to effectively immunize the industry from civil suits. Once passed, the suits fell one by one. All except Gary’s.

The case had notably approached a significant milestone that similar lawsuits had not. As the year began, it was nearing the end of the discovery phase, where the two sides would continue an exchange of thousands of records, providing plaintiffs a chance to glimpse inside the internal decisions and policies of gun manufacturers. It is unclear when or if that process will resume.