WASHINGTON — A majority of Supreme Court justices appeared to agree with New Jersey Gov. Chris Christie on Monday that prohibiting sports betting in most states is unconstitutional.

With the outgoing governor seated in the front row, several of the court’s conservative justices said a 1992 federal law impermissibly directed states to keep their bans on the books. They were joined by Justice Stephen Breyer, one of the court’s four liberals.

“It falls within commandeering,” Breyer told Paul Clement, the lawyer representing the NCAA and professional sports leagues who have sought to block New Jersey from legalizing sports betting. 

New Jersey repealed part of its ban on sports betting in 2014 in a way that would allow the state to regulate it. U.S. Deputy Solicitor General Jeffrey Wall argued that only a more sweeping repeal that allowed all forms of sports gambling would have been permissible. 

That argument didn’t sit well with Chief Justice John Roberts, who said the federal government was preferring no regulation at all to state regulation.

“You have no problem if there’s no prohibition at all, and anybody can engage in any kind of gambling they want?” he said. “A 12-year-old can come into the casino?”

Some of the court’s more liberal justices, however, seemed to support the 25-year-old federal law. Justice Elena Kagan said Congress merely was preempting state law when it passed the Professional and Amateur Sports Protection Act, something it does regularly.

Congress passed PASPA almost unanimously to preserve what lawmakers at the time felt was the integrity of the games. Sponsored by then-Sen. Bill Bradley, a New Jersey Democrat who once played small forward for the New York Knicks, the law preceded the advent and growth of Internet gambling. 

Because Nevada had legalized sports betting in 1949, it was grandfathered in. Delaware, Montana and Oregon were allowed to keep previously authorized sports lotteries. Other states were given a year’s leeway to get in on the action, but New Jersey failed to take advantage of the offer.

Christie, who appeared confident outside court after the hour-long argument, said the option should be open. “If the people of those states…