President Donald Trump scored a major legal victory on immigration on Wednesday as the Supreme Court gave him the go-ahead to proceed with a new policy barring asylum for migrants who pass through another country en route to the U.S.

The high court order allows the policy, which is expected to drastically reduce asylum granted to Central American migrants, to be implemented across the U.S.-Mexico border as court challenges over its legality play out.

While the Supreme Court’s emergency stay is technically an interim one, it appears unlikely that the justices would hear arguments on the dispute this term, creating the prospect that Trump’s policy could be in effect through next year’s election regardless of how the high court ultimately rules.

Only two justices noted dissent from the Supreme Court’s action, Democratic appointees Sonia Sotomayor and Ruth Bader Ginsburg.

The president was quick to tout the ruling as a triumph for his efforts to dramatically reshape immigration policy.

“BIG United States Supreme Court WIN for the Border on Asylum!” Trump tweeted on Wednesday evening.

A top Trump administration immigration official, acting U.S. Citizenship and Immigration Services Director Ken Cuccinelli, used a similarly exuberant tone to celebrate the court’s action.

“YUGE Win at #SCOTUS today!” he wrote on Twitter.

As is customary in stay rulings, the justices joining in the decision did not explain their rationale. However, Sotomayor wrote an opinion that Ginsburg joined denouncing the court’s action as a moral abdication that puts the lives of thousands at risk.

Sotomayor also stressed that the new regulation — issued as an “interim final rule” — didn’t undergo a period of public comment before taking effect.

“It is especially concerning, moreover, that the rule the government promulgated topples decades of settled asylum practices and affects some of the most vulnerable people in the Western Hemisphere — without affording the public a chance to weigh in,” she wrote.

Immigrant-rights advocates used stark language to decry the court’s ruling.

“The human toll of today’s asylum ban stay will be horrific,” Omar Jadwat, an American Civil Liberties Union attorney, wrote on Twitter.

Rebecca Kirzner of the refugee-support group HIAS tweeted: “The Supreme Court's decision to allow the asylum ban to go into effect (for now) is.... just devastating. Anyone who has passed through another country (ie, anyone but Mexicans) is going to be denied asylum. For some, that will be a death sentence. The cruelty is overwhelming.”

The Supreme Court’s action on Wednesday evening put a hold on a series of lower-court rulings that blocked Trump’s policy nationwide and then narrowed those injunctions to effectively cover only a portion of the border with Mexico. The high court ruling leaves the Trump administration free to apply the new policy to immigrants who crossed the southwestern border from mid-July onward. It does not apply to those who arrived earlier or who enter the U.S. by boat or plane.

U.S. District Court Judge Jon Tigar — an appointee of President Barack Obama — twice blocked the policy nationwide, only to have the 9^th U.S. Circuit Court of Appeals cut the injunctions back to the border states in its geographic jurisdiction, California and Arizona. That left the administration free to implement the policy along the border in Texas and New Mexico, which are under the authority of other appeals courts.

In a statement on Wednesday night, White House spokesman Hogan Gidley echoed the administration’s bitter complaints about a single judge’s seeking to block a major policy shift nationwide.

“The district court’s erroneous nationwide injunction was another in a series of overreaching orders that allowed a single, non-elected district court judge to override policy decisions for the entire Nation,” Gidley wrote. “While there is much more work still to be done, thankfully the Supreme Court took a decisive step here and rejected the lower court’s egregious ruling.”

The so-called safe-third-country policy, issued as a fast-track regulation in July, was blocked by Tigar on the grounds that it appeared to violate longstanding federal law and was enacted arbitrarily.

The Supreme Court stay will terminate if the high court later declines to take up the case.

In her dissent, Sotomayor called the Trump administration’s request to halt the lower court’s injunction an “extraordinary” step.

“Unfortunately, the court acquiesces,” she wrote. “Because I do not believe the government has met its weighty burden for such relief, I would deny the stay.”

The injunctions blocking the policy were issued as part of a suit brought in July by the ACLU, the Southern Poverty Law Center and the Center for Constitutional Rights on behalf of immigrant-rights groups.

The 9^th Circuit has scheduled arguments for Dec. 2 on Tigar’s initial preliminary injunction. Even if the appeals court rules quickly, it will probably be past the time for the Supreme Court to take up that ruling this term, unless the justices agree to an unusual acceleration of the case.

Another suit challenging the policy is pending in Washington, but the judge in that case already turned down an injunction request. Even if he reverses himself or appeals judges step in, it seems likely that any injunction that might be issued in that case would face a similar fate as Tigar’s injunctions did Wednesday.

Jadwat, the ACLU attorney, also expressed bitterness that the high court was effectively nullifying the impact of the lower-court litigation.

“Calling balls and strikes, or announcing the winner before the game’s been played?” Jadwat wrote on Twitter, referencing Chief Justice John Roberts’ assurance during his confirmation hearings that the Supreme Court should act like a baseball umpire. The tweet was later deleted.