WASHINGTON – The Justice Department on Friday called on the Supreme Court to halt a judge’s order to restart a Trump-era program that was causing migrants crossing the southern border to seek asylum to await their cases in Mexico , often in life-threatening situations.

The move came in response to one of two court rulings this week that marked a backlash in President Biden’s efforts to reverse his predecessor’s tough immigration policies.

On Thursday, a federal appeals court in Texas dismissed an attempt by the Biden administration to halt a court order reinstating the controversial migrant protection protocols program, also known as “Remain in Mexico” asylum policy, underway during the Trump administration. The order should take effect on Saturday.

And in a separate case, a federal judge in Texas temporarily blocked the Biden administration’s short-term strategy of limiting arrests of undocumented immigrants by prioritizing those who most threatened national and public security. A Justice Department spokeswoman said the agency is reviewing Judge Drew B. Tipton’s 160-page verdict of the U.S. District Court for the Southern District of Texas and lawyers are considering next steps.

Taken together, the trials threaten two of the Biden government’s earliest efforts to reshape the country’s immigration system. Another blow came in July when a federal judge ruled that an Obama-era program protecting hundreds of thousands of undocumented young adults from deportation was illegal.

The judges’ decisions and the administration’s appeal to the Supreme Court on Friday, emphasized the role of the courts as the primary venue for shaping polarizing immigration policy, one legal challenge after another – a strategy that immigration advocates have refined during the Trump administration.

“Those who oppose the Biden government’s immigration agenda take every opportunity to ask political questions and have them answered in favorable courts,” said Tom K. Wong, director of the US Immigration Policy Center at the University of California, San Diego said.

The order for the Biden administration to restore Trump policies that forced asylum seekers to wait in Mexico while their cases were being handled in the United States came from Judge Matthew J. Kacsmaryk of the U.S. District Court for the Northern District of Texas.

He and Judge Tipton were both appointed by President Donald J. Trump. Of the three judges on the Fifth District Court of Appeal who on Thursday denied the government’s motion to stop the “stay in Mexico” ruling, two were appointed by Trump; the third was appointed by President George W. Bush.

On appeal to the Supreme Court, government attorneys said the reintroduction of asylum policy on Saturday was “almost impossible” and would cause “irreparable harm”. Critics said it would place asylum seekers in dangerous gathering environments at a time when the highly contagious Delta variant fueled a surge in coronavirus cases.

It was initially unclear what exactly the order would set in motion on Saturday or whether Mexico would allow the program to resume.

The program was also litigated during the Trump administration.

“You will likely see opponents of the Biden administration’s future policies using the courts to hold back progress, which only adds to the importance of Congressional action,” Wong said.

The most recent example is efforts to prevent the administration from prioritizing undocumented immigrants to be arrested.

In February, the Biden administration issued its preliminary arrest priorities for immigration and customs enforcement, a marked departure from the Trump administration’s policy of arresting undocumented immigrants for any immigration violations. The Biden team ordered ICE officials to give priority to the arrest of undocumented persons who pose a risk to national and public security, as well as those who recently illegally crossed the border. The Obama administration has similar enforcement priorities.

Texas Attorney General Ken Paxton celebrated the injunction on the priorities of Mr. Biden’s arrest, calling it “another Texas win over Biden.”

Texas is a party in both cases and this year has borne the brunt of the unusually high number of illegal border crossings, with many migrant families and children from Central America arriving in the state’s Rio Grande Valley and overwhelming border officials. The state has taken several measures to challenge the immigration policies of the Biden government; Earlier this summer, Republican Governor Greg Abbott ordered state law enforcement agencies to arrest migrants for trespassing in an attempt to tackle illegal immigration – because, he said, the Biden administration did not.

Alejandro N. Mayorkas, the Secretary of Homeland Security, has been working to outline permanent arrest priorities for ICE that would replace the tentative ones currently under attack. It was not immediately clear whether the judge’s ruling would apply to the administration’s final arrest priorities.

If the Biden government cannot continue with its immigration arrest strategy, the postponement will likely continue to weigh on an immigration detention system that is already near full. ICE arrests have so far decreased by more than half this year compared to the same period in 2020, according to immigration statistics, in part due to pandemic-related rules to limit the number of people in meeting places and temporary arrest priorities.

Mr. Wong said that even if Republicans were to challenge arrest priorities, it would not change the reality that there was not enough room.

“And so the policy of ‘enforcement en masse’ does not take into account finite resources,” he said, “including limited detention capacities.”

The government is also waiting for a judge to rule on a lawsuit that would prevent them from continuing a public health rule that the Trump administration put in place at the start of the pandemic to help many asylum-seeking families arriving at the border to refuse. Immigration advocates filed the lawsuit last year, when Vice President Kamala Harris, then a Senator from California and a presidential candidate, argued against the rule.

The plaintiffs’ attorneys hoped to reach an agreement with the Biden administration. But discussions collapsed last month when the White House decided not to lift the health rule anytime soon due to the overwhelming number of migrants arriving at the southern border and the risk of further Covid-19 infections.

If the courts ultimately order the administration to repeal the public health rule, it will expand the federal government’s enforcement capabilities even further.

Charlie Savage contributed to the coverage.