(CNN) — The Supreme Court said Tuesday that the North Carolina Supreme Court did not violate the elections clause of the US Constitution when it invalidated the state’s 2022 congressional map, rejecting a broad version of a controversial legal Independent State Legislature theory pushed by supporters of former President Donald Trump.

Chief Justice John Roberts wrote the 6-3 opinion.

The case had captured the nation’s attention because Republican lawmakers in North Carolina were asking the justices to adopt a long-dormant legal theory and hold that state courts and other state entities have a limited role in reviewing election rules established by state legislatures when it comes to federal elections.

“State courts retain the authority to apply state constitutional restraints when legislatures act under the power conferred upon them by the Elections Clause,” Roberts wrote.

The court allowed that federal courts can have some role supervising state courts in certain circumstances, with Roberts writing that “state courts do not have free rein.”

“Federal courts,” Roberts said, “must not abandon their duty to exercise judicial review.”

“When state legislatures act pursuant to their Elections Clause authority, they engage in lawmaking subject to the typical constraints on the exercise of such power,” he wrote. “In sum, our precedents have long rejected the view that legislative action under the Elections Clause is purely federal in character, governed only by restraints found in the Federal Constitution.”

Roberts was joined by fellow conservative justices Brett Kavanaugh and Amy Coney Barrett and liberal justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson.

The decision will have ramifications for the future of elections nationwide.

Former President Barack Obama said the case had the potential to “dismantle our system of checks and balances.”

“This ruling is a resounding rejection of the far-right theory that has been peddled by election deniers and extremists seeking to undermine our democracy,” Obama said in a statement.

The North Carolina controversy arose after the state Supreme Court struck down the state’s 2022 congressional map as an illegal partisan gerrymander, replacing it with court drawn maps that favored Democrats.

After the state high court ruled, North Carolina Republican lawmakers appealed the decision to the US Supreme Court, arguing that the state Supreme Court had exceeded its authority.

They relied upon the Elections Clause of the Constitution that provides that rules governing the “manner of holding Elections for Senators and Representatives” must be prescribed in “each state by the legislature thereof.” Under the independent state legislature theory, the lawmakers argued, state legislatures should be able to set rules with little to no interference from the state courts.

The justices heard oral arguments in the case last winter and some of them appeared to express some support for a version of the doctrine.

But after the case, known as Moore v. Harper, was argued at the Supreme Court, and before the justices could render an opinion, new developments occurred in North Carolina.

After the last election, the North Carolina Supreme Court flipped its majority to Republican. In April, the newly composed North Carolina Supreme Court reversed its earlier decision and held that the state Constitution gives states courts no role to play in policing partisan gerrymandering.

With the US Supreme Court rejecting the lawmakers’ theory that state courts could not police federal election rules, lawyers for the legislature’s opponents celebrated Tuesday’s ruling.

“As we argued to the Supreme Court, the independent state legislature theory was contrary to precedent and would have called into question hundreds of state constitutional provisions and decisions,” said former Acting US Solicitor General Neal Katyal, who represented Common Cause, one of the voting rights groups that challenged the Republican-drawn map. “Today’s ruling affirms the crucial role state courts play in overseeing federal elections.”

Dissent by court’s far-right wing

Justice Clarence Thomas wrote a dissent, joined in full by Justice Neil Gorsuch and in part by Justice Samuel Alito, arguing that the court should have dismissed the case as moot, given how circumstances around the case evolved after the justices heard it.

“In short, this case is over, and petitioners won,” Thomas wrote, referring to how a newly-reconstituted North Carolina Supreme Court reheard the case this year and reversed its decision in favor of the defenders of the Republican-drawn map. “It follows that no live controversy remains before this Court.”

In a section joined only by Gorsuch, Thomas went on to criticize the merits of the majority’s opinion Tuesday.

Thomas accused the majority opinion of opening “a new field for Bush-style controversies over state election law – and a far more uncertain one” – an allusion to the blockbuster election disputes that arose in the 2000 presidential race.

Thomas wrote that he “fear[ed]” that the framework put forward by the majority “will have the effect of investing potentially large swaths of state constitutional law with the character of a federal question not amenable to meaningful or principled adjudication by federal courts.”

Ruling cheered by voting rights attorneys

The court’s ruling was praised by a large swath of voting rights attorneys, including the lawyers who represented the voters who had challenged the North Carolina redistricting map and who opposed the independent state legislature theory in court.

“This ruling is a complete victory for our democratic system and makes clear that state legislatures cannot ignore or defy state law when regulating federal elections,” said Jessica Ring Amunson and Sam Hirsch, partners at the law firm Jenner & Block who represented one of the voter advocacy groups involved in the case.

Hilary Harris Klein – a senior counsel for voting rights at Southern Coalition for Social Justice, another voting rights group involved in the litigation – said that Tuesday’s “decision will ensure that voters will continue to have the full protection of state constitutions against harmful and anti-democratic voter suppression and election manipulation.”

North Carolina House Speaker Tim Moore, who was pressing the Supreme Court to adopt the independent state legislature theory, noted in a statement Tuesday the win his side had secured at the state Supreme Court when it reversed its previous ruling this year and upheld the map the legislature had drawn.

“Today the United States Supreme Court has determined that state courts may rule on questions of state law even if it has an impact on federal elections law,” said Moore, who as lead petitioner, gave the case half its name. “Ultimately, the question of the role of state courts in congressional redistricting needed to be settled and this decision has done just that.”

This story has been updated with additional details.

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