President Joe Biden is expected to sign an executive order Tuesday allowing him to temporarily seal the U.S. border with Mexico to migrants when crossings surge, a move that would suspend longtime protections for asylum-seekers in the United States.

Biden’s senior aides have told members of Congress in recent days to expect him to sign the order at the White House alongside mayors from south Texas, according to several people familiar with the plans.

“I’ve been briefed on the pending executive order,” said Rep. Henry Cuellar, D-Texas, who has previously called on the president to bolster enforcement at the border. “I certainly support it because I’ve been advocating for these measures for years. While the order is yet to be released, I am supportive of the details provided to me thus far.”

The order would be the most restrictive border policy instituted by Biden, or any other modern Democrat, and echoes an effort in 2018 by President Donald Trump to curb migration that Democrats assailed and federal courts blocked.

Although the executive action is almost certain to face legal challenges, Biden is under intense political pressure to address illegal immigration, a top concern of voters before the presidential election in November.

The decision shows how the politics of immigration have tilted sharply to the right over the course of Biden’s presidency. Polls suggest growing support — even in the president’s party — for border measures that Democrats once denounced and Trump championed.

The specifics

The order would allow border officials to prevent migrants from claiming asylum and rapidly turn them away once crossings exceed a certain threshold. (Minors who cross alone are likely to be exempt from the restrictions, according to an official briefed on the order.)

Typically, migrants claiming asylum are released into the United States to wait for court appearances, where can they can plead their cases. But a huge backlog means those cases can take years to come up.

Government officials discussed allowing Biden to shut down the border this year if an average of more than 5,000 migrants per day tried to cross illegally in a week, or more than 8,500 tried to cross on a given day.

In recent days, White House officials have discussed a limit of 2,500 illegal crossings per day. That would mean the border could be closed to asylum-seekers as soon as Biden signs the executive order because daily totals currently exceed that number.

Administration officials have said that executive action was not their preference and that they believe any order would face a legal challenge.

“Legislation is what is needed,” Alejandro Mayorkas, the homeland security secretary, said last month.

“Executive action will be challenged,” he added. “I am confident in that. And then the question will be: What is the outcome of those proceedings? Legislation is a more certain delivery of solution.”

The American Civil Liberties Union led the charge against the Trump administration’s attempt to block asylum in 2018, which resulted in the policy being stopped by federal courts. The group has signaled that it is ready to challenge any order that limits asylum at the border.

Political concerns

Although Republicans have long assailed Democrats over border security, Biden in recent years has also faced calls by members of his party for stronger enforcement.

Rep. Tom Suozzi, D-N.Y., who won a special House election this year partly by calling for stricter immigration measures, sent a letter to Biden last month encouraging him to issue an executive order that would restrict asylum.

“I think it’s very, very important, not only for Democrats or for political purposes, but it’s important for America,” Suozzi said in an interview. “This is something the people are very concerned about.”

But there are also political risks to issuing the executive order. Republicans have in recent days questioned why Biden did not take unilateral action at the border sooner. In January, he told reporters that he had “done all I can do” at the border and that he needed help from Congress.

“The American people know better,” Speaker Mike Johnson, R-La., wrote in a social media post Monday.