The Supreme Court has handed President Donald Trump a major victory by narrowing nationwide injunctions that blocked his executive order purporting to end the right to birthright citizenship.

In doing so, the court sharply curtailed the power of individual district court judges to issue injunctions blocking federal government policies nationwide.

The justices, in a 6-3 vote along ideological lines, said that in most cases, judges can only grant relief to the individuals or groups who brought a particular lawsuit and may not extend those decisions to protect other individuals without going through the process of converting a lawsuit into a class action — a special type of litigation that requires challengers to clear procedural hurdles.

“The universal injunction was conspicuously nonexistent for most of our Nation’s history,” Justice Amy Coney Barrett wrote in the majority opinion.

The ruling Friday came in connection with three lawsuits in which judges granted nationwide injunctions against an executive order Trump signed on the first day of his second term, seeking to deny American citizenship to children born in the U.S. to foreigners on short term visas and those without legal status. The judges said the order is patently unconstitutional because it conflicts with Supreme Court precedent and the text of the 14th Amendment, which says that “all persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States.”

The Supreme Court did not rule Friday on the underlying constitutionality of Trump’s executive order. The three liberal justices, in dissent, said the president’s directive is clearly illegal.

“The Court’s decision to permit the Executive to violate the Constitution with respect to anyone who has not yet sued is an existential threat to the rule of law,” Justice Ketanji Brown Jackson wrote in a dissent.

While the court’s ruling appears to be a major victory for Trump, it does include an important caveat: The court left open the possibility of nationwide relief in lawsuits brought by state governments. That’s because, Barrett wrote, it’s possible a nationwide injunction could be necessary to fashion “complete relief” for states in the lawsuits they bring. Barrett said the court intentionally declined to answer that question and would allow lower courts to ponder it in the meantime.

Kyle Cheney contributed to this report.