WASHINGTON – The Supreme Court freed the Trump administration Wednesday to implement its policy denying asylum to migrants at the southern border who have not sought protection from another country en route.

The brief order signaled the justices' more tolerant view of efforts to restrict asylum seekers while legal challenges work their way through the courts. In December, they refused to let the administration deny asylum at locations other than official ports of entry.

Associate Justices Ruth Bader Ginsburg and Sonia Sotomayor dissented from the brief order. No other justices announced their votes.

"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," Sotomayor wrote.

The new policy, announced in July, was challenged as even more restrictive than the first by the American Civil Liberties Union. Migrants from Central America are unlikely to win asylum in Mexico or elsewhere on their way to the southern border.

Lee Gelernt, deputy director of the ACLU's Immigrants' Rights Project, cautioned that the high court's order was "just a temporary step."

"We’re hopeful we’ll prevail at the end of the day," Gelernt said. "The lives of thousands of families are at stake."

White House principal deputy press secretary Hogan Gidley praised Wednesday's order, saying in a statement that "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."

And Justice Department spokesman Alexei Woltornist said DOJ "is pleased that the Supreme Court intervened in this case, which enables full implementation of this important immigration rule across the entire southern border."

Woltornist added that "This action will assist the Administration in its objectives to bring order to the crisis at the southern border, close loopholes in our immigration system, and discourage frivolous claims."

But Rep. Jerrold Nadler, D-N.Y., chair of the House Judiciary Committee, and Rep. Zoe Lofgren, D-Calif., chair of the panel's subcommittee on immigration and citizenship said they were "gravely disappointed" the administration will be allowed to implement a "shameful policy that that effectively shuts the door on people seeking asylum at our Southern border unless they are Mexican Nationals."

The two Democratic lawmakers added that "The asylum systems and infrastructure of the countries in our hemisphere are woefully inadequate and unable to meet the needs of migrants coming from countries in Central America.”

U.S. District Judge Jon Tigar had blocked the policy from going into effect nationwide only days after it was unveiled, ruling that it violated laws passed by Congress.

"While the public has a weighty interest in the efficient administration of the immigration laws at the border, it also has a substantial interest in ensuring that the statutes enacted by its representatives are not imperiled by executive fiat," Tigar wrote.

A federal appeals court panel later upheld Tigar's ruling but limited its impact to the Ninth Circuit, which includes California and Arizona but no other states bordering on Mexico. Then just two days ago, Tigar reinstated the ban nationwide – only to have the appeals court temporarily block it from taking effect.

When the Supreme Court refused to green-light the separate policy regarding asylum seekers who cross the border illegally, Chief Justice John Roberts joined the court's four liberal justices, and four other conservative justices dissented.

This time, apparently Roberts – perhaps joined by liberal Justices Stephen Breyer and Elena Kagan – sided with the administration. Court orders are unsigned.

Solicitor General Noel Francisco argued that the policy was intended to screen out asylum seekers "who declined to request protection at the first opportunity."

"It alleviates a crushing burden on the U.S. asylum system by prioritizing asylum seekers who most need asylum in the United States," Francisco wrote. "The rule also screens out asylum claims that are less likely to be meritorious by denying asylum to aliens who refused to seek protection in third countries en route to the southern border."

Gelernt responded that the ban "would eliminate virtually all asylum at the southern border, even at ports of entry, for everyone except Mexicans."

"The court should not permit such a tectonic change to U.S. asylum law," he wrote. "Allowing the ban to go into effect would not only upend four decades of unbroken practice, it would place countless people, including families and unaccompanied children, at grave risk."

Under federal law, applicants can be denied asylum if the U.S. has a formal "safe-country" agreement with a third country. But those do not exist with Mexico and Guatemala, the two countries traversed by migrants from El Salvador and Honduras.

The administration policy represents one of its many attempts to limit or halt migrants from requesting asylum at the southwest border.

Immigration explainer:Is Trump following through on his campaign promises?

In June 2018, the Justice Department introduced a policy cutting off asylum for victims of domestic abuse and gang violence. In November, the Justice and Homeland Security departments issued the plan to block migrants who enter the country illegally from requesting asylum. Both those policies were blocked by federal judges.

Tigar's denial of the latter plan led to a rare war of words between President Trump and Roberts. In a series of tweets, Trump bashed the Ninth Circuit as politically biased. That prompted a rare retort from Roberts, who said there are no "Obama judges" or "Trump judges" but "an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them."

In December, the administration tried a different approach. The Department of Homeland Security announced a “Remain in Mexico” plan that forces migrants seeking asylum to return to Mexico to await the outcome of their applications.

That policy was temporarily blocked by a federal judge, but the Ninth Circuit appeals court handed Trump a rare victory and allowed it to go into effect. As a result, some 38,000 migrants await their fates across the border.

Contributing: Savannah Behrmann, USA TODAY