WASHINGTON —The Supreme Court on Friday blocked enforcement of a Louisiana law that could force all but one of the state’s abortion clinics to close, a sign that a similar law in Texas also could be in peril.

The justices effectively reversed an order by the federal appeals court in New Orleans that allowed Louisiana to begin enforcing its 2014 clinic regulation law even as it is being challenged in the courts.

The law requires doctors who provide abortions to have admitting privileges at nearby hospitals.

Two clinics, in Boisier City and Baton Rouge, that had already closed in response to the appellate ruling will reopen and a third clinic in Shreveport that faced imminent closure will remain open, said the Center for Reproductive Rights, which is representing the clinics.

Louisiana Attorney General Jeff Landry said the state would continue defending the law. “We remain confident that we will prevail on the merits,” Landry said.

The high court’s order, with only Justice Clarence Thomas noting his dissent, came two days after the justices heard arguments in a major abortion case from Texas and just hours after they voted in a private meeting on that case.

A vote for the clinics in Louisiana could signal that Justice Anthony Kennedy, whose vote is crucial to both sides, also will be a decisive fifth vote in favor of abortion clinics in Texas.

The court is operating with eight justices since Antonin Scalia’s death last month.