The Supreme Court just paved the way for legalized sports gambling in America — and potentially setting off an internecine fight among conservatives.

After a very long battle over the boundaries of federal and state sovereignty, the Supreme Court effectively threw out the Professional and Amateur Sports Protection Act (PASPA) in its entirety, freeing states to legalize sports betting. In Murphy v. NCAA, the court ruled 7-2 that PASPA's prohibition on state legislatures from passing laws favorable to sports betting — but which did not impose a federal ban on gambling directly — violated the Tenth Amendment.

In one sense, this ruling should please conservatives. The Supreme Court has not often gone out of its way to strengthen the Tenth Amendment, a key constitutional touchstone for small-government activists. Murphy v. NCAA had already been cited as a potential game-changer for limiting Washington's power — an antidote to previous expansive precedent on the Commerce Clause, starting with Wickard v. Filburn.

Justice Samuel Alito didn't upend Wickard or limit the Commerce Clause in his governing opinion. However, he did set a hard limit on Congress' ability to dictate what state legislatures can and cannot do without enacting a full federal prohibition on an activity, which PASPA avoided. The Constitution allots limited authority to Congress, Alito wrote, but "all other legislative power is reserved for the states, as the Tenth Amendment confirms." Alito added: "And conspicuously absent from the list of powers given to Congress is the power to issue direct orders to the governments of the states."

The court ruled that PASPA crossed that line and violated the "anti-commandeering" separation between federal and state sovereignties. "It is as if federal officers were installed in state legislative chambers and were armed with the authority to stop legislators from voting on any offending proposals," Alito concluded. "A more direct affront to state sovereignty is not easy to imagine."

That does not leave Congress without any options, however. Alito allowed in his opinion that Congress has the authority through the dreaded Commerce Clause to directly outlaw sports gambling, but it cannot pass a law prohibiting states from making sports gambling legal if Congress does not outlaw it themselves. "Congress can regulate sports gambling directly," Alito wrote, "but if it elects not to do so, each state is free to act on its own."

Very likely, that is precisely what will happen. But not before conservatives duke it out.

One of the authors of PASPA, Sen. Orrin Hatch (R-Utah), has already announced plans to double down on his original bet. "The problems posed by sports betting," Hatch argued in his statement, "are much the same as they were 25 years ago. But the rapid rise of the internet means that sports betting across state lines is now just a click away. We cannot allow this practice to proliferate amid uneven enforcement and a patchwork race to the regulatory bottom."

When he co-wrote PASPA in 1992, Hatch was one of the stronger conservative voices in the upper chamber. At that time, the three-legged stool of the right still prevailed: social conservatism, fiscal discipline, and a strong military. Hatch's PASPA fell clearly into the first leg, a moral stricture against vice that has the potential to corrupt not just governments but souls.

The world has changed since those days, and so has conservatism. While abortion still occupies its own place in the conservative agenda, the prominence of other social issues has fallen in favor of a more libertarian approach. Younger voters see issues like gambling and recreational use of marijuana as personal choices more than moral or public policy issues. In March, for the first time ever, Gallup found a majority of Republicans in favor of marijuana legalization, noting that "the trajectory of Americans' views on marijuana is similar to that of their views on same-sex marriage over the past couple of decades." Speaking of which, GOP voter support for same-sex marriage nearly hit a majority in a Gallup poll last year as well.

So far Hatch hasn't specified what exactly he will propose in place of PASPA. The court's ruling in Murphy makes it clear that anything short of a federal ban on sports betting won't cut constitutional muster. The recent trend against prohibitions, especially at the federal level, all but guarantees that such a proposal won't get far. Hatch will argue, as he did in his statement on Monday, that the federal government needs to ban sports gambling to preserve the integrity of athletics. That, however, ignores the fact that the original PASPA left a wide gap by allowing Nevada to continue its sports-gambling operations as a "grandfathering" approach. If Hatch goes for a full ban, the only option that the court appears to have left Congress, it could pit Republicans against some of their biggest benefactors, including Nevada casino magnate Sheldon Adelson.

Hatch will retire from the Senate by the end of the year. Don't place any large bets on a new sports-gambling ban getting enough votes to pass.