WASHINGTON (CN) — Six justices on the Supreme Court shut the door Tuesday on an extreme legal theory that could give state legislatures unchecked power to influence elections, but they left their own authority to do the same unchecked.

Moore v. Harper asked the justices to decide what role state courts have in deciding questions about the administration of elections. Republican lawmakers in North Carolina argued that the legislature should rein supreme on these issues, authorized to enact rules about elections without any interference from the rest of the governing structure, in contradiction to the checks and balances considered a hallmark of the American democratic system.

Chief Justice John Roberts led the Supreme Court on Tuesday in a resounding rejection of the independent state legislature theory.

“The Elections Clause does not insulate state legislatures from the ordinary exercise of state judicial review,” the Bush appointee wrote.

Roberts’ reasoning is based on originalism, tracing the authority of courts to decide these matters back to the founding. But it was a more recent citation that caught the attention of court watchers.

“Members of this Court last discussed the outer bounds of state court review in the present context in Bush v. Gore,” Roberts wrote.

The blockbuster 2000 ruling effectively decided the election in favor of the Republican candidate. George W. Bush had appealed to the Supreme Court after his Democratic opponent, Al Gore, persuaded the Florida Supreme Court to order a recount of selective ballots in the state. Bush had only a slim lead over Gore at the time, and his win at the U.S. Supreme Court blocked the recount.

Love it or hate it, the court’s ruling in Bush appeared to be a one-of-its-kind occurrence. In fact, the ruling has never even been cited in a majority opinion — that is until Tuesday.

“The court back in Bush v. Gore made as clear as it could that they thought it was sui generis, and they, having decided it, wanted to put it back in a box on the shelf and never touch it again — do not open,” Frederick Lawrence, a distinguished lecturer at Georgetown Law, said in a phone interview. “So it’s a little surprising to see they went back to it.”

Bush is credited as the birthplace of the independent state legislature theory. A three-justice concurrence led by Chief Justice William Rehnquist suggested the state high court exceeded its bounds of ordinary judicial review and, therefore, usurped the legislature’s authority.

“When Chief Justice Rehnquist wrote his concurrence in Bush v Gore for three justices — which endorsed a different version of the doctrine — there was a lot of criticism, a lot of support, but that kind of lay dormant for all these years,” Richard Pildes, a constitutional law professor at New York University, said during a press briefing on the case.

The minority concurrence inspired future litigation but had not been accepted as doctrine. In Moore, the independent state legislature theory, or a version of it, curried more favor.

“Now, a majority of the court has not only endorsed the position of the Rehnquist concurrence in Bush v. Gore but actually extended it to the domain of state constitutional decision making,” Pildes said.

This version is not the one put forward by Republican lawmakers in North Carolina, but it gives credence to the thinking like never before.

“The court resoundingly rejected … the most extreme version of the theory — the version that would really have dramatically destabilized federal elections,” Pildes said. “But at the same time, they actually did endorse a weaker version of the theory. And I think we no longer call it a theory; it’s a doctrine now.”

Tuesday’s ruling is also interesting because Roberts was joined in the majority by Justices Brett Kavanaugh and Amy Coney Barrett — all three were in private practice in 2000 and helping the Bush legal team when the dispute with Gore went to the high court.

“Justice Kavanaugh, don’t forget, was one of the prime advocates in that case, and a lot of his argument and reasoning made its way into Chief Justice Rehnquist’s opinion,” Lawrence said. “Then here the court comes back and cites that opinion, as does Justice Kavanaugh. So in a way, whereas one might have thought he would want to stay away from that, he actually grabbed it with both hands.”

Legal experts say there is only a small crack in the doorway now for cases to be brought under this doctrine. Moore says that federal courts can step in when a state court has strayed too far from the state constitution. Importantly, the justices did not agree on a framework to decide how this happens.

“This gives a very big leeway to state courts,” David Gans, director of the human rights, civil rights & citizenship program at the Constitutional Accountability Center, said in an interview. “Federal courts can’t second guess state court rulings simply because they disagree with the state courts’ interpretation and would have interpreted the state constitutional language differently. So I think if courts heed the Constitution’s text and history as the court did today, any review in the future of state court interpretations of state constitutional law has to be highly deferential.”

By dispensing with the most extreme version of the independent state legislature theory, the court provided some assurances that free and fair elections would be maintained in 2024. But legal analysts say the narrow ground provided by the court could still present challenges.

“That is a shadow now hanging over the 2024 elections,” Pildes said. “It does introduce some uncertainty that we won’t get worked out until we have a series of further decisions.”