A federal appeals court on Thursday ruled against the Biden administration’s efforts to delay implementation of an order that requires it to reinstate the Trump-era Migrant Protection Protocols (MPP) — yet another legal defeat for the Biden administration on immigration.

The panel of the 5th Circuit Appeals Court declined to stay a ruling by Judge Matthew Kacsmaryk issued last week that orders the Biden administration "to enforce and implement MPP in good faith" until it has been "lawfully rescinded" in compliance with the Administrative Procedure Act, and until the federal government has enough detention capacity to detail all migrants subject to mandatory detention. 

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Kacsmaryk allowed a seven-day appeal window to the ruling, but it was denied by a three-judge panel.

"Even if the Government were correct that long-term compliance with the district court’s injunction would cause irreparable harm, it presents no reason to think that it cannot comply with the district court’s requirement of good faith while the appeal proceeds," the ruling said.

The "Remain in Mexico" policy was put in place in 2019 by the Trump administration and involved sending migrants back to Mexico, rather than being released into the U.S., as their asylum proceedings were heard.

The policy, in cooperation with Mexico, resulted in court tents being set up along the border in places like Laredo, Texas, where migrants could briefly enter for their hearings before going back to Mexico.

The Trump administration argued that the policy ended "catch-and-release," which it saw as a major pull factor drawing migrants north. 

Critics said the Remain in Mexico policy was cruel and led to migrants being put in danger in camps across the border.

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The Biden administration promised to end the policy and began processing migrants enrolled in MPP into the U.S. shortly after entering office. In June, it formally ended the program.

Missouri and Texas sued the administration, claiming that ending the policy was both illegal in the way that it was done, and that it harmed both border states and states deeper in the interior by encouraging migrants and therefore fueling the crisis at the southern border.

"We are hopeful for a favorable ruling because it is clear that the Biden administration didn’t consider anything relevant to how it was working or notice and comment, and obviously we have a crisis at the border now," Missouri AG Eric Schmitt told Fox News in an interview last month. "Anyone who is paying attention knows we have a 21-year high in border crossings, drug traffickers, and human traffickers have been emboldened, and that affects not just Texas but states like Missouri."

The lawsuit claimed some of the migrants released would commit crimes in their states, that it would lead to an increase in human trafficking, and that it would lead to higher costs for the states in areas like education and healthcare.

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The ruling found that the termination of MPP "has contributed to the current border surge" and that Department of Homeland Security counsel had conceded as much. The judge also noted the increase in border apprehensions from fewer than 80,000 in January to about 173,000 in April when the lawsuit was filed. In July, there were more than 212,000 encounters at the border.

The ruling also accused Homeland Security Secretary Alejandro Mayorkas of not having considered warnings that ending MPP would lead to a surge in migrants crossing the border, and that he didn’t consider the costs to the states. Kacsmaryk also said he found DHS arguments, such as the potential negative effect on diplomatic relations, "unpersuasive."

While Kacsmaryk said the court does not have the authority to tell a DHS employee which individual migrants must be enrolled in MPP,  he ruled that it can enjoin a blanket policy that again allows front line Customs and Border Protection (CBP) officers to use MPP to return migrants to Mexico.

Schmitt on Friday hailed the 5th Circuit's denial of a stop to the ruling as yet another victory for his state.

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"Last night, we won another major victory against Biden’s Department of Justice in our lawsuit to reinstate the ‘Remain in Mexico’ policy, with the 5th Circuit denying their request for an emergency stay," he said in a statement. "Last week, we delivered a massive win for border security and the rule of law, and that winning streak continues today. I will continue to fight to ensure that this successful Trump-era policy is re-implemented, and that the crisis at the border is quelled."

It marks the latest defeat for the Biden administration on immigration. On Thursday, a Texas federal judge imposed a preliminary injunction on the Biden administration’s rules for Immigration and Customs Enforcement (ICE) officers that significantly narrowed the categories of illegal immigrants being targeted for arrest and deportation.