WASHINGTON >> A united conservative majority of the Supreme Court ruled Friday that federal judges lack the authority to grant nationwide injunctions, but the decision left unclear whether President Donald Trump’s restrictions on birthright citizenship could soon take effect in parts of the country.

The outcome represented a victory for Trump, who has complained about judges throwing up obstacles to his agenda. Nationwide, or universal, injunctions had emerged as an important check on the Republican president’s efforts to expand executive power and remake the government and a source of mounting frustration to him and his allies.

But the court left open the possibility that the birthright citizenship changes could remain blocked nationwide. Trump’s order would deny citizenship to U.S.-born children of people in the country illegally or temporarily.

The cases return to lower courts, where judges will have to decide how to tailor their orders to comply with the high court ruling, written by Justice Amy Coney Barrett. Enforcement of the policy can’t take place for 30 days, Barrett wrote.

Even then it’s unclear whether the court’s decision could produce a confusing patchwork of rules that might differ in the 22 states that sued over the Trump order and the rest of the country.

The justices agreed with the Trump administration, as well as President Joe Biden’s Democratic administration before it, that judges are overreaching by issuing orders that apply to everyone instead of just the parties before the court. Judges have issued more than 40 such orders since Trump took office for a second term in January.

The administration has filed emergency appeals with the justices of many of those orders, including the ones on birthright citizenship. The court rarely hears arguments and issues major decisions on its emergency, or shadow, docket, but it did so in this case.

Federal courts, Barrett wrote, “do not exercise general oversight of the Executive Branch; they resolve cases and controversies consistent with the authority Congress has given them. When a court concludes that the Executive Branch has acted unlawfully, the answer is not for the court to exceed its power, too.”

The president, speaking in the White House briefing room, said that the decision was “amazing” and a “monumental victory for the Constitution,” the separation of powers and the rule of law.

Senate Democratic leader Chuck Schumer of New York wrote on X that the decision is “an unprecedented and terrifying step toward authoritarianism, a grave danger to our democracy, and a predictable move from this extremist MAGA court.”

Justice Sonia Sotomayor, writing in dissent for the three liberal justices, called the decision “nothing less than an open invitation for the government to bypass the Constitution.” This is so, Sotomayor said, because the administration may be able to enforce a policy even when it has been challenged and found unconstitutional by a lower court.

The administration didn’t even ask, as it has in other cases, for the lower-court rulings to be blocked completely, Sotomayor wrote. “To get such relief, the government would have to show that the order is likely constitutional, an impossible task,” she wrote.

But the ultimate fate of the changes Trump wants to make were not before the court, Barrett wrote, just the rules that would apply as the court cases continue.

Rights groups that sued over the policy filed new court documents following the high court ruling, taking up a suggestion from Justice Brett Kavanaugh that judges still may be able to reach anyone potentially affected by the birthright citizenship order by declaring them part of “putative nationwide class.” Kavanaugh was part of the court majority Friday but wrote a separate concurring opinion.

States that also challenged the policy in court said they would try to show that the only way to effectively protect their interests was through a nationwide hold.

“We have every expectation we absolutely will be successful in keeping the 14th Amendment as the law of the land and of course birthright citizenship as well,” said Attorney General Andrea Campbell of Massachusetts.

Birthright citizenship automatically makes anyone born in the United States an American citizen, including children born to mothers in the country illegally. The right was enshrined soon after the Civil War in the Constitution’s 14th Amendment.