President Biden fought on Friday to save lots of a bipartisan immigration deal from collapse in Congress, vowing to close down the border if the plan grew to become regulation even because the Republican speaker pronounced it useless on arrival within the Home.

In a written assertion that got here as Senate negotiators scrambled to finalize a deal that former President Donald J. Trump is pressuring Republicans to oppose, Mr. Biden used his most stringent language but in regards to the border, declaring it “broken” and in “crisis” and promising to halt migration instantly if Congress sends him the proposal.

“What’s been negotiated would — if passed into law — be the toughest and fairest set of reforms to secure the border we’ve ever had in our country,” he stated. “It would give me, as president, a new emergency authority to shut down the border when it becomes overwhelmed. And if given that authority, I would use it the day I sign the bill into law.”

The pending compromise wouldn’t give him a lot alternative. Below the rising deal, the administration can be required to close down the border to migrants making an attempt to enter with out prior authorization if encounters rise above 5,000 on any given day — a threshold that has been surpassed routinely in latest months.

Mr. Biden’s contemporary efforts to salvage the deal got here hours after Speaker Mike Johnson sought to choke off the final remaining glimmers of hope that it’d survive, repeating that the settlement would nearly definitely be a nonstarter within the Republican-led Home.

“If rumors about the contents of the draft proposal are true, it would have been dead on arrival in the House anyway,” Mr. Johnson wrote in a letter to Home G.O.P. lawmakers.

It was the newest grim prediction for the proposed border settlement after the highest Senate Republican conceded this week that Mr. Trump’s opposition had made the plan politically tough for the social gathering to embrace, all however killing its probabilities.

Mr. Biden’s Friday night assertion amounted to a counterpunch in opposition to Mr. Trump’s efforts to torpedo the deal, pitting the present and former commanders in chief in opposition to one another in a high-stakes battle over what’s shaping as much as be a central difficulty within the presidential marketing campaign.

Because the immigration plan teeters on Capitol Hill, the destiny of further support for Ukraine hangs within the stability as effectively, with hard-right Home Republicans additionally dug in in opposition to it and threatening to depose Mr. Johnson if he seeks to push it by means of over their objections.

In his letter, Mr. Johnson stated the Home would transfer forward subsequent week with its drive to question Alejandro N. Mayorkas, the homeland safety secretary, and doubled down on his calls for that Congress embrace both an immigration crackdown invoice the Home handed final 12 months or an equally extreme measure.

“Since the day I became speaker, I have assured our Senate colleagues the House would not accept any counterproposal if it would not actually solve the problems that have been created by this administration’s subversive policies,” he wrote.

Mr. Biden’s phrases have been unlikely to maneuver the rising variety of skeptical Republicans who’ve argued that the president already has the instruments and the chief energy he must dramatically limit migration into the nation — and refuses to make use of them.

“Many of our constituents have asked an important question: ‘What is the point of negotiating new laws with an administration that will not enforce the laws already on the books?’” Mr. Johnson wrote in his letter. “If President Biden wants us to believe he is serious about protecting our national sovereignty, he needs to demonstrate his good faith by taking immediate actions to secure it.”

The letter mirrored a stance Mr. Johnson and different hard-right Republicans within the Home have maintained for months, repeatedly dismissing the border enforcement measures below dialogue within the Senate as inadequate. It got here as Republican proponents of the deal within the Senate toiled to construct wanted G.O.P. help to push it ahead. That job has grown far more tough as Mr. Trump has gained floor in his quest for the social gathering’s presidential nomination.

Senator Mitch McConnell of Kentucky, the minority chief, instructed fellow Republicans behind closed doorways this week that Mr. Trump’s hostility to the plan and his rising dominance within the main had put them “in a quandary.”

Mr. McConnell, a chief Republican proponent of sending extra support to Ukraine, has been a vocal supporter of the border deal that members of his social gathering have insisted upon as the value of their backing for continued help for Kyiv.

The bipartisan group of senators that has been working for months to strike a compromise to crack down on rampant migration and drug trafficking throughout the southern border with Mexico has come to an settlement in latest days on a set of coverage adjustments. They embody measures to make it tougher to safe asylum and improve detention services.

The deal would additionally improve the variety of out there visas by 50,000, together with many that may be green-card eligible, and set a purpose of deciding asylum instances inside 90 days.

The group has not but agreed on how a lot cash to commit to the trouble.

Many Republicans are upset that the deal doesn’t embody a selected restriction on parole, the administration’s authority to let migrants not in any other case legally licensed to enter the nation dwell and work in the USA on a short lived foundation. In his letter on Friday, Mr. Johnson repeated his demand for extra restrictive adjustments, corresponding to putting strict limits on parole and reviving the Trump-era “Remain in Mexico” coverage that compelled migrants who couldn’t be saved in detention services to attend exterior the USA till their courtroom dates.

And a few Republican opponents of the border compromise have questioned the knowledge of bothering to contemplate it within the Senate if their counterparts within the Home are decided to dam or kill it.

“If you’re going to take a tough vote, you want it to actually accomplish something,” stated Senator J.D. Vance, Republican of Ohio. “If it’s not going to pass the House, then it doesn’t make a ton of sense to force a vote on your membership that isn’t going to accomplish anything from a policy perspective, and it’s going to cause a lot of problems politically.”

There have been political dangers for Mr. Biden and Democrats as effectively in embracing robust border measures which have enraged progressives.

Immigration advocates took Mr. Biden’s assertion as a betrayal from a president who had campaigned on taking a humane strategy to the border. Some warned him in opposition to getting into a race with Republicans over who may outmuscle a border crackdown that the advocates stated would result in chaos and struggling.

“What does President Biden want his legacy to be?” stated Heidi Altman, director of coverage for the Nationwide Immigrant Justice Heart. “The president is asking to trade the lives and rights of people seeking safety for a failed political strategy, and it’s shameful.”

Michael D. Shear, Zolan Kanno-Youngs and Hamed Aleaziz contributed reporting.