Washington — The Supreme Court handed President Donald Trump a significant defeat on Monday, turning down the administration’s plea for a quick ruling on the president’s power to end special protections for so-called Dreamers.

The court’s decision not to hear the administration’s appeal immediately could keep in place a legal shield for the nearly 700,000 young immigrants for the rest of this year, and perhaps longer.

The Justice Department had sought to leap-frog the U.S. appeals courts in California and New York. The department had asked for an “immediate review” of a nationwide order by U.S. District Judge William Alsup in San Francisco that required the government to maintain for now the Obama-era program known as Deferred Action for Childhood Arrivals, or DACA.

The action the administration sought was rare. It has been nearly 30 years since the Supreme Court granted review of a district judge’s ruling before an appeals court could weigh in. And the court said Monday it had no interest in following that course in the DACA case.

The justices, without dissent, turned down the administration’s petition “without prejudice,” meaning that the government could return to the high court once the appeals court rules.

“It is assumed that the Court of Appeals will proceed expeditiously to decide this case,” the justices noted.

The action by the high court was procedural in nature, and not a ruling on the substance of the case, but its impact could be significant because it keeps in place Alsup’s nationwide injunction.

Last fall, when he announced that he would end the DACA program, President Trump gave Congress until March 5 to pass legislation to resolve the legal status of the Dreamers.

But lawmakers have failed to agree on new legislation. Last week, the Senate considered four proposals to change the immigration laws, but could not muster the required 60 votes to proceed on any of them.

With the nationwide court order in place, Trump’s March 5 deadline is essentially dead. In their appeal, administration lawyers said the injunction would likely last well into 2019 if the appeals run their normal course in the lower courts.

Even if the court of appeals does act “expeditiously,” as the justices suggested, a ruling would be unlikely before summer. That would mean the earliest the case could return to the Supreme Court would be in the fall, with a ruling possible by the end of the year.

That’s assuming a speedy path for the litigation. A scenario in which the case doesn’t return to the high court until a year from now is quite possible.

Congress could change the situation at any time, but it would need to agree on a new law.

After Alsup issued his order, U.S. Solicitor General Noel Francisco surprised many observers by not asking the Supreme Court to grant a stay that would put the order on hold. He asserted that such a stay would result in an “abrupt shift” in the enforcement policy, while the administration favored an “orderly wind-down of the DACA policy.”

Instead, Francisco insisted the high court should grant review of Alsup’s opinion, hear arguments in the spring and then reverse the judge’s decision in a written ruling.