A total of 21 US states are suing the Biden administration's decision to end ex-president Donald Trump's use of public health laws to deport illegal immigrants.
That was after 18 more states joined the lawsuit against the Centres for Disease Control and Prevention (CDC) among others, which has announced it will lift the order under Section 265 of Title 42 of the United States Code.
The code allows the Surgeon General — with presidential approval — to block entry from any country where a dangerous epidemic is raging. The Trump administration used the law to expedite deportations of illegal immigrants crossing the land border from Mexico.
The suit was originally brought by Arizona, Louisiana and Missouri, but others including Florida have since joined.
"Ending Title 42 would be a disaster and further the chaos at the southwest border that is making it easier for drug cartels and human smugglers to advance their illicit practices in our country," Florida Attorney General Ashley Moody said in a statement, adding that it was "reckless" for the CDC to lift Trump's order.
Respondents named in the lawsuit include CDC Director Dr Rochelle Walensky, the Department of Justice and Attorney General Merrick Garland, the Department of Homeland Security and Secretary Alejandro Mayorkas and the Department of Health and Human Services and Secretary Xavier Becerra.
Many states, including some run by President Joe Biden's Democratic Party, fear that lifting the order will worsen the already dire humanitarian situation at the border, across which at least 1.7 million people were trafficked in 2021 and where an estimated 8,000 are arriving every day.
Both Arizona's Democrat senators, Kyrsten Sinema and Mark Kelly have criticised the move to drop Title 42.
"The administration's extension of public health emergency authorities proves the need to delay lifting Title 42 to protect the health and safety of Arizona communities and migrants," Synema said on Thursday. "I'll keep pushing for transparency and accountability from the administration to help secure the border, keep Arizona communities safe and ensure migrants are treated fairly and humanely".
Fellow Democrat Senator Maggie Hassan of New Hampshire recently travelled to the US-Mexico border to witness the situation for herself.
"My trip to the southern border reinforced my concerns about the administration pre-emptively ending Title 42," Hassan said. "Border agents were very clear with me that the end of Title 42 will lead to a steep increase of attempted crossings that they will not be able to effectively handle because they don't have enough resources."
Republicans have sought to block the Biden administration's move by tabling an amendment to a $10 billion COVID-19 spending bill that would keep the Title 42 rules in place. That prompted an attack from the White House.
"it is disappointing that Senate Republicans voted down consideration of a much-needed bill to purchase vaccines, boosters, and life-saving treatments for the American people," Biden's Press Secretary Jen Psaki said in a statement hours after Republican senators blocked the bill from passing. "As we have repeatedly said, there are consequences for Congress failing to fund our COVID Response. The program that reimbursed doctors, pharmacists and other providers for vaccinating the uninsured had to end today due to a lack of funds."