The Supreme Court is temporarily blocking an order that would lift pandemic-era restrictions on asylum seekers. But it is leaving open the prospect of lifting the restrictions by Wednesday.

The order Monday by Chief Justice John Roberts comes as conservative states are pushing to keep limits on asylum seekers that were put in place during the beginning of the coronavirus pandemic. They are appealing to the U.S. Supreme Court in a last-ditch effort before the limits are set to expire.

In the one-page order, Roberts granted a stay pending further order and asked the government to respond by 5 p.m. Tuesday. That is just hours before the restrictions are slated to expire on Wednesday.

The order by Roberts means the high-profile case that has drawn intense scrutiny will go down to the wire.

The immigration restrictions, often referred to as Title 42, were put in place under then-President Donald Trump in March 2020 and have prevented hundreds of thousands of migrants from seeking asylum in the U.S. in recent years. But as they’re set to expire, thousands more migrants are packed in shelters on Mexico’s border with the U.S.

Immigration advocates sued to stop the use of Title 42 to limit who can apply for asylum, saying that the policy goes against American and international obligations to people fleeing to the U.S. to escape persecution. And they’ve argued that things like vaccines and treatments for the coronavirus have made the policy outdated.

Conservative-leaning states have argued that lifting of Title 42 will lead to a surge of migrants into their states and take a toll on government services like health care or law enforcement. They also charge that the federal government has no plan to deal with an increase in migrants.