(CNN) Supreme Court Chief Justice John Roberts on Monday put a temporary hold on the termination of a controversial Trump-era immigration policy known as Title 42 that was set to end on December 21, leaving it in place for now.
But in a brief order Roberts signaled that the court wants to act quickly and asked the Biden administration to respond by 5 p.m. ET Tuesday to an emergency appeal filed by a group of Republican-led states.
The brief order from Roberts means the policy that allows officials to swiftly expel migrants at the US border will stay in effect at least until the justices decide the emergency application. The order does not necessarily reflect the final outcome of the case.
The states had raced to the Supreme Court earlier in the day in an emergency bid to keep in place a Trump-era immigration policy that is set to go off the books Wednesday.
A federal district court judge had vacated the policy last month, calling Title 42 "arbitrary and capricious." The judge said the program could remain in effect until December 21.
Already, federal officials and border communities have been bracing for an expected increase in migrant arrivals as early as this week, as the issue of immigration continues to ignite both sides of the political divide. The Department of Homeland Security has been putting in place a plan for the end of the program that includes surging resources to the border, targeting smugglers and working with international partners.
"As required by the Supreme Court's administrative stay order, the Title 42 public health order will remain in effect at this time and individuals who attempt to enter the United States unlawfully will continue to be expelled to Mexico," the department said in a statement following Roberts' order. "While this stage of the litigation proceeds, we will continue our preparations to manage the border in a safe, orderly, and humane way when the Title 42 public health order lifts."
Arizona Attorney General Mark Brnovich -- who took the lead for the states -- said in a statement earlier Monday that "getting rid of Title 42 will recklessly and needlessly endanger more Americans and migrants by exacerbating the catastrophe that is occurring at our southern border," adding: "Unlawful crossings are estimated to surge from 7,000 per day to as many as 18,000."
Brnovich had told the justices in court papers that they should put the lower court ruling on hold. As an alternative, he said that the justices should grant an "immediate" temporary injunction to maintain the status quo and also consider whether to skip over the appeals court and agree to hear arguments on the merits of the issue themselves.
"Failure to grant a stay here will inflict massive irreparable harms on the States, particularly as the States bear many of the consequences of unlawful immigration," Brnovich argued.
Late Friday night, the DC Circuit US Court of Appeals ruled against the states, holding that they waited an "inordinate" amount of time before trying to get involved in the case. That order triggered the emergency application at the high court, which was addressed to Roberts, who oversees the DC-based appellate appeals court that ruled in the case.
Roberts is likely to refer the matter to the full court.
"This is a longstanding problem, more people are fleeing persecution, gang violence, failed states and climate change than ever before," said Stephen Yale-Loehr of Cornell Law School, who has been critical of the policy. "Even without Title 42, we would have more people than ever before trying to enter the United States," he added.
"Title 42 is not an effective way to manage our borders, instead, we need to both enact immigration reform in the United States and work with other countries so that people don't feel so desperate to leave in the first place," Yale-Loehr said.
In the early days of the coronavirus pandemic, the US Centers for Disease Control and Prevention issued a public health order that officials said aimed to stop the spread of Covid-19. The border restrictions were controversial from the moment the Trump administration announced them.
In the case at hand, six families that unlawfully crossed the US-Mexico border and were subject to the Title 42 process brought the original challenge.
In court papers, their lawyers at the American Civil Liberties Union argue that Covid-19 was always a thinly veiled pretense to increase immigration control. "There is no legal basis to use a purported public health measure to displace the immigration laws long after any public health justification has lapsed," said Lee Gelernt, an ACLU lawyer representing the migrant families in the suit.
The Biden administration objects to the states' attempt to intervene in the ongoing dispute and has said it is prepared to allow the program to end, but stresses it is still appealing the district court opinion to preserve the authority of the government to impose public health orders in the future.
White House press secretary Karine Jean-Pierre said earlier Monday that the administration would have more details Tuesday on its plans ahead of the rule's planned expiration and reiterated the US would continue to enforce its immigration laws amid the current influx.
Inside the White House, the pause on the termination will not have any effect on what have been intensive behind-the-scenes preparations for the end of the authority, according to a White House official.
While the Department of Homeland Security serves as the lead agency on the issue, it has been a central focus for the last several weeks inside the West Wing, with senior White House officials playing a significant role in the internal debates over policy options to address an expected surge of migrants at the border. There are no plans to slow the ongoing effort, the official said, given the possibility any delay is only brief in nature.
"We've always been aware of the role the courts have in this process, but it's not something that changes the approach," the official said.
This story has been updated with additional details.