Updated 4:20 p.m. | The Supreme Court ruled Monday that Congress took the wrong path when it effectively banned sports gambling, in an opinion that appears to open the door for New Jersey and other states to get in on the action unless Washington steps in again.

In a 6-3 opinion, the justices struck down key provisions of a 1992 federal law, known as the Professional and Amateur Sports Protection Act, finding that it violates the 10th Amendment’s delegation of regulatory power to the states.

In doing so, the majority opinion written by Justice Samuel A. Alito Jr. said that Congress can directly act to regulate sports gambling — but it can’t do it by telling states what laws they can and can’t pass.

The 1992 law controls how states regulate their citizens, Alito wrote, and that violates what is known as the anti-commandeering doctrine. He added that such a provision is akin to putting state legislatures under the direction of Congress on the controversial subject of gambling, where “Americans have never been of one mind.”

“The legalization of sports gambling requires an important policy choice, but the choice is not ours to make,” Alito wrote. “Congress can regulate sports gambling directly, but if it elects not to do so, each State is free to act on its own.”

Watch: What to Watch as Supreme Court Prepares Major Decisions

Chief Justice John G. Roberts Jr., and Justices Anthony M. Kennedy, Clarence Thomas, Elena Kagan and Neil Gorsuch joined the majority opinion. Stephen G. Breyer also joined Alito’s majority opinion when it comes to one provision of the law.

But Breyer also joined a dissent, written by Justice Ruth Bader Ginsburg and also joined by Justice Sonia Sotomayor, that argues the majority went too far when it struck down a second provision of the 1992 law that would have accomplished Congress’ goal of stopping sports gambling.

Ginsburg wrote that the majority deploys “a wrecking ball destroying the Professional and Amateur Sports Protection Act” rather than use a narrower ruling to “salvage the statute.”

Congress has the authority to do what it did in the second provision, Ginsburg wrote, which is to regulate sports gambling by instructing states and private parties from operating sports-gambling schemes.

“Deleting the alleged ‘commandeering’ directions would free the statute to accomplish just what Congress legitimately sought to achieve: stopping sports-gambling regimes while making it clear that the stoppage is attributable to federal, not state, action,” Ginsburg wrote in the dissent.

Breyer said Congress might have seen the second provision as a backup way to “keep sports gambling from spreading” just in case states found a way to authorize sports gambling schemes. Had the majority kept that section it would have made “New Jersey’s victory here mostly Pyrrhic.”

New Jersey lawmakers, including Republicans Leonard Lance and Frank A. LoBiondo and Democrat Frank Pallone Jr., have backed legislation in recent years that would allow sports betting in the Garden State.

Pallone said on Twitter that the decision “is a win for NJ & our entire country” and pointed to the need for legislation because of the ruling. He filed a bill that would detail consumer protections and other gaming requirements.

“Now, Congress must ensure that consumer protections are in place in any state that decides to implement sports betting,” said Pallone, the ranking member on the House Energy and Commerce Committee.

Sen. Orrin G. Hatch, who helped write the 1992 law, said Monday he plans to introduce new legislation to “protect honesty and principle in the athletic arena” and address internet gambling across state lines. 

“At stake here is the very integrity of sports,” the Utah Republican said in a statement.

Democratic Sen. Catherine Cortez Masto of Nevada said she would work to maintain her state’s leadership in the gaming industry. “In Nevada, we know better than anyone that sports betting that is regulated responsibly and efficiently can be a great source of revenue for boosting local economies,” she said in a news release.

The decision comes in two cases out of New Jersey. After a lawsuit from the NCAA and others, an appeals court ruled that the 1992 law means New Jersey officials can neither license sports wagering or repeal state sports betting prohibitions in casinos and racetracks.

Billions of dollars in sports gambling already takes place in the United States, and in a sign of the interest in the case, 18 states filed a brief siding with New Jersey and its argument that Congress can’t prevent states from enacting, modifying or repealing their own laws.

The American Gaming Association said the decision paves “the way for the legalization of sports betting in all 50 states,” and called the decision “a victory for the millions of Americans who seek to bet on sports in a safe and regulated manner.”

“Today’s ruling makes it possible for states and sovereign tribal nations to give Americans what they want: an open, transparent, and responsible market for sports betting,” said Geoff Freeman, the group’s president and chief executive officer.

“Through smart, efficient regulation this new market will protect consumers, preserve the integrity of the games we love, empower law enforcement to fight illegal gambling, and generate new revenue for states, sporting bodies, broadcasters and many others,” Freeman said.

The cases are Gov. Phil Murphy et al v. National Collegiate Athletic Association et al, Docket No. 16-476, and New Jersey Thoroughbred Horsemen’s Association Inc. et al v. National Collegiate Athletic Association et al, Docket No. 16-477.