And given the sheer number of cases now working through the courts, a lot more time will be spent in courtrooms no matter who wins.
“We will see a lot of tax dollars and government resources that should be used to stop gun crime being used to defend gun laws that are lifesaving and wildly popular," said Jonathan Lowy, chief counsel and vice president at Brady, the gun control group.
Congress broke through years of deadlock to pass a modest gun violence prevention package weeks ago, and the House voted to renew a ban on high-powered semi-automatic weapons, though that effort is likely doomed in the Senate as Republicans push back on firearms restrictions and say recent spikes in gun violence should be met with a stepped-up police response.
The Supreme Court decision struck down a New York law requiring people to demonstrate a particular need to get a license to carry a concealed gun in public, saying it violates Second Amendment rights. Several other states including California, Hawaii, Maryland, Massachusetts, New Jersey and Rhode Island have similar laws expected to be directly impacted by the ruling.
In Massachusetts, for example, police chiefs can no longer deny or impose restrictions on licenses just because the applicant doesn’t have a “good reason” to carry a gun. New York quickly passed a new concealed-weapon law, but Republicans there predict it will also end up being overturned.
In its New York ruling, the high court's conservative majority also changed a test lower courts had used for evaluating challenges to gun laws.
Judges should no longer consider whether the law serves public interests like enhancing public safety, the opinion authored by Justice Clarence Thomas said. Instead, they should only weigh whether the law is “consistent with the Second Amendment’s text and historical understanding.”
“Basically, the Supreme Court has given an invitation for the gun lobby to file lawsuits against virtually every gun law in America,” Lowy said.
The Supreme Court has ordered lower courts to take another look at several other cases under the court's new test. Among them: laws in California and New Jersey that limit the amount of ammunition a gun magazine can hold and a 2013 ban on "assault weapons" in Maryland.
Gun rights groups are also challenging similar bans in California, New York, New Jersey and Delaware.
“The rifles at issue in this case are the sorts of bearable arms in common use for lawful purposes that responsible and peaceable people across the United States possess by the millions. And they are, moreover, exactly what they would bring to service in militia duty, should such be necessary,” a New Jersey lawsuit brought in June by the Firearms Policy Coalition says, referencing the language of the Second Amendment.
The ruling also has come up in challenges to restrictions on gun possession for 18- to 20-year-olds in Texas and Pennsylvania. And it has been cited in a case challenging a federal ban on gun possession for people convicted of nonviolent crimes punishable by more than a year behind bars, as well as a prohibition on concealed guns on the subway in Washington, D.C.
In addition, a gun rights group is suing Colorado over the state’s 2013 ban on magazines that hold more than 15 rounds, saying the high court ruling reinforces the group’s argument that it infringes on Second Amendment rights. And the ruling has public defenders in New York City asking judges to drop gun possession cases.
Not all those lawsuits will necessarily be successful. The Texas attorney general, for example, argues the Supreme Court ruling doesn't affect the state's age limit law, and more state and local governments can certainly defend their gun laws as being in line with U.S. history.
Adam Skaggs, chief counsel and policy director at the Giffords Law Center to Prevent Gun Violence, predicted that when the dust settles, only laws “along the margins” will eventually be struck down.
“Most judges are going to see these for what they are, which is overreaching and lacking in any merit,” he said.
Backers of gun restrictions can also look to a concurring opinion from Justice Brett Kavanaugh.
Joined by Chief Justice John Roberts, Kavanaugh stressed that the Second Amendment does allow for a “variety” of gun regulations. He cited the use of background checks and mental health records as part of a licensing process to carry a gun and noted that states can forbid the carrying of firearms in “sensitive places” such as schools and government buildings.
But the Colorado decision handed down last month, while still early in the process, was a rosy sign for gun rights groups.
U.S. District Court Judge Raymond Moore, who was nominated by President Barack Obama, said he was sympathetic to the town's goal of preventing mass shootings like the one that killed 10 people at a grocery store in nearby Boulder last year. But Moore said he didn't know of "historical precedent" for a law banning "a type of weapon that is commonly used by law-abiding citizens for lawful purposes," so the gun rights groups have a strong case against the ordinance.
Encouraged by that decision, Taylor D. Rhodes, the executive director of the Rocky Mountain Gun Owners, told The Associated Press that his group was considering going after other gun measures in Colorado, where Democrats hold the majority in the state legislature and the governor's office.
Referring to the Supreme Court’s ruling, Rhodes said: “The Bruen decision gave us a 4-ton wrecking ball."
This story has been corrected to reflect that Brady's chief counsel is Jonathan Lowy, not Lowry.
Richer reported from Boston.