The Biden administration on Tuesday asked Chief Justice John Roberts to rule against 19 GOP-led states that initiated court action to keep the controversial Title 42 policy in place.

The administration was responding to Roberts’s administrative stay from Monday in which he temporarily halted the end of the policy, set to end Wednesday.

Title 42 has taken center stage in the political debate over immigration and border policy.

Most Republicans and some Democrats say it is essential to border control, while immigration advocates and most Democrats oppose Title 42 mainly because it undermines the asylum system.

In its response to Roberts, the administration publicly recognized that the public health reasoning behind the policy is no longer valid.

Under Title 42, U.S. border officials are allowed to skip asylum processing for migrants from many countries, instead quickly expelling the migrants back to their home country, or in the case of many Central Americans, back across the border to Mexico.

While Title 8 makes it somewhat harder to quickly expel migrants, it allows border officials to fully screen for asylum claims, and it imposes criminal penalties on repeat unauthorized border crossers.

Title 42 is legally based on a Centers for Disease Control and Prevention (CDC) order to keep coronavirus from spreading through the border, but the CDC’s involvement in its implementation is now known to have been the result of political pressure from the Trump White House.

Though Preolgar did not raise questions about the original public health considerations behind Title 42, she did tell Roberts they are no longer valid, as the CDC issued a termination of its emergency order in April.

“The government has been barred from implementing that termination by a preliminary injunction in separate litigation, which the government has appealed. But the government could scarcely have sought extraordinary relief to perpetuate a CDC-imposed public-health measure that CDC itself has concluded is no longer justified under the public-health laws,” wrote Preolgar.

But the applicants in the matter — the states who oppose lifting Title 42 — had also made the case that lifting Title 42 would further fuel chaos at the border.

The Biden administration, which has appealed the original ruling that forced it to end Title 42, told Roberts the Department of Homeland Security is ready to go back to Title 8.

“The government is prepared to do that, including by surging resources and invoking its Title 8 authorities to implement new policies in response to the temporary disruption

that is likely to occur whenever the Title 42 orders end,” wrote Preolgar.

Still the administration asked for a short reprieve in lifting Title 42, keeping the policy in place until Dec. 27 if Roberts rules before Friday, or giving the administration two business days to prepare if the ruling comes after that time.

“That brief continuation of the stay would allow the government to again prepare for a full return to operations under Title 8, with new policies tailored to the consequences of the end of the Title 42 orders — a complex, multi-agency undertaking with policy, operational, and foreign relations dimensions that has been paused or partially unwound in light of the administrative stay,” wrote Preolgar.

Along with the government’s opposition filing, attorneys for respondents in the original Title 42 lawsuit filed an opposition to the states’ application for a stay.

The respondents’ lawyers, who include immigrant and civil rights groups like the ACLU, accused the states of creating a delay in the government’s plans to wind down Title 42, perpetuating harms for migrants.

“The government recognizes that the end of the Title 42 orders will likely lead to disruption and a temporary increase in unlawful border crossings. The government in no way seeks to minimize the seriousness of that problem. But the solution to that immigration problem cannot be to extend indefinitely a public-health measure that all now acknowledge has outlived its public-health justification,” wrote Solicitor General Elizabeth Prelogar.

Updated: 6:39 p.m.