The ruling by the Ninth Circuit Court of Appeals on Friday applied across the southern border and stripped the administration of one of its key asylum policies, which went into effect in January 2019. The Ninth Circuit also issued a separate ruling that upheld a lower court's block on an administration policy denying asylum to those who crossed the southern border illegally.
The so-called "remain in Mexico" program required migrants, many of whom are from Central America, to stay in Mexico until their respective court dates in the US. On Thursday, acting Customs and Border Protection Commissioner Mark Morgan said 59,000 people have been enrolled in the program, formally known as the Migrant Protection Protocols program.
Late Friday night, the Ninth Circuit put its ruling on hold after a request by the Trump administration and set a timeline for replies. The policy can continue in the interim.
The Trump administration had asked the court to put a temporary hold on its ruling as soon as Saturday. Lawyers for the Justice Department said they feared "a rush on the southern border by some of the 25,000 or more individuals who are in Mexico under MPP and may now seek immediate entry into this country." The Justice Department also asked for an administrative stay until March 6 so it could appeal the case to the Supreme Court.
Trump administration officials have repeatedly cited the policy as a success and attributed it in part to the drop in arrests along the southern border. Immigrant advocates, however, have argued that the policy put migrants in harm's way as they waited in makeshift camps.
"The MPP has had serious adverse consequences for the individual plaintiffs," wrote Judge William Fletcher.
He continued: "Plaintiffs presented evidence in the district court that they, as well as others returned to Mexico under the MPP, face targeted discrimination, physical violence, sexual assault, overwhelmed and corrupt law enforcement, lack of food and shelter, and practical obstacles to participation in court proceedings in the United States. The hardship and danger to individuals returned to Mexico under the MPP have been repeatedly confirmed by reliable news reports."
The Justice Department and White House denounced the ruling in statements.
"Today's decision out of the Ninth Circuit once again highlights the consequences and impropriety of nationwide injunctions," a department spokesman said. "The Ninth Circuit's decision not only ignores the Constitutional authority of Congress and the Administration for a policy in effect for over a year, but also extends relief beyond the parties before the Court."
White House press secretary Stephanie Grisham said the ruling is "another reckless nationwide injunction threatening our constitutional structure, obstructs the Executive Branch from faithfully executing the immigration laws passed by Congress and from protecting American citizens and legal immigrants."
"We remain committed to using every lawful means necessary to secure the border, and we are considering all available legal options to seek further review of this decision," Grisham added.
The American Civil Liberties Union heralded Friday's ruling. "The court forcefully rejected the Trump administration's assertion that it could strand asylum seekers in Mexico and subject them to grave danger. It's time for the administration to follow the law and stop putting asylum seekers in harm's way," said ACLU attorney Judy Rabinovitz in a statement.
The group also filed a lawsuit Friday challenging the administration's transfer of military funds for the construction of the border wall.
Judge Ferdinand Fernandez dissented, arguing that the court is bound by the reasoning behind the panel's previous decision.
The Ninth Circuit's ruling acknowledges what immigrant advocates, lawyers and lawmakers have repeatedly warned of: that migrants are at risk while waiting in Mexico for their court date.
"Uncontested evidence in the record establishes that non-Mexicans returned to Mexico under the MPP risk substantial harm, even death, while they await adjudication of their applications for asylum," Fletcher writes.
"They sleep under that tent," DeLauro told CNN. "We have created here an unbelievable outrage against humanity."
The House Judiciary Committee had also announced an investigation into the policy, requesting documents and information from acting Department of Homeland Security Secretary Chad Wolf.
It's unclear what will happen to the migrants already subject to the "remain in Mexico" policy.
"Today's ruling is an important victory for the tens of thousands of vulnerable migrants from all over the world who have been trapped in Mexico -- making it nearly impossible for them to exercise their legal rights," said Melissa Crow, an attorney at the Southern Poverty Law Center. "It is also an important step in addressing the U.S. government-created humanitarian crisis that has resulted from the implementation of this policy."
This story has been updated with additional background information and reaction.