As senators gathered on the floor for a typical Monday night vote at the end of October, Senator Mitch McConnell, the Kentucky Republican and minority leader, approached Senator Chuck Schumer, his Democratic counterpart, with some unsettling news: Border security was going to have to be part of any package to free up endangered assistance for Ukraine.
To Mr. Schumer of New York, the majority leader, the ultimatum revived unpleasant memories of his participation in difficult immigration negotiations in 2013 that yielded a compromise, only to collapse despite strong bipartisan support in the Senate. But saying no could doom the Ukraine aid and leave Democrats holding the bag. He and his staff grappled with the problem for a week, then gathered for a conference call on Sunday, Nov. 5. A bold new approach took hold.
“We had an epiphany — sort of, lightning strikes,” Mr. Schumer recalled in an interview. “Do border. If we did it right and were tough about it, it’s a win for us. And it helps us with Ukraine because so many of our people care about Ukraine, they will vote for a good border bill.”
The abrupt change in conventional Democratic thinking had profound significance for the ensuing four months on Capitol Hill. It touched off a circuitous series of events — including some near-death experiences — that paved the way for the Senate’s approval early Tuesday of $95 billion in aid to Ukraine, Israel and U.S. allies in the Indo-Pacific. The final package notably did not contain new border security provisions, after Senate conservatives opted to kill that element of the legislation despite their initial insistence that it be included.
The tanking of the immigration proposal, hammered out over weeks of talks between the designees of Mr. Schumer and Mr. McConnell, ultimately cleared the way for passage of the foreign aid bill. Enough Republicans — 22 in the end — were unwilling to desert Ukraine, and many of them believed that Mr. Schumer and his fellow Democrats had made a good-faith effort to strike a border security deal that was sabotaged by members of their own party.
The possibility that Republicans would bolt from their own deal had occurred to Mr. Schumer from the start, given his previous experience.
“We knew it way back then,” he said.
But Mr. Schumer saw a political upside should that occur: Democrats would be able to say they tried and point to the Republican opposition for failing to halt a surge of migrants illegally crossing the U.S. border with Mexico.
“It’s a win if Republicans abandon us at the last minute,” Mr. Schumer said in an interview, explaining his calculation, “because if Democrats could put together a tough, bipartisan bill on border, it would not take border away as an issue for the Republicans, but it would give us a 50-50 chance to combat it.”
The strategy seemed to pay off almost immediately with the victory of Tom Suozzi, a Democrat, in the special House election in New York on Tuesday. He was able to deflect his Republican opponent’s attacks against him on immigration by accusing her and her party of playing politics with the border in rejecting the Senate deal.
“Unfortunately, too many Republicans succumbed to the ministrations of Donald Trump,” Mr. Schumer said after the Senate vote.
The senator acknowledged that the border talks were touch and go throughout. He regularly urged Senator Christopher S. Murphy, the Connecticut Democrat handling the talks for his party, to stick with it and be willing to give significant ground, he said. Mr. Schumer suggested to Biden administration officials that they insert Alejandro N. Mayorkas, the homeland security secretary, directly into the Senate talks, which they did.
As Thanksgiving came and went, Mr. Schumer said he also sought more engagement from President Biden, top White House officials and Mr. McConnell through his staff to expand the buy-in.
He named a handful of Senate Democrats with credibility as strong supporters of Ukraine and good relationships with Republicans to begin persuading Republicans that Democrats were sincere about taking tough steps to halt the border surge. And he was in contact with progressive and Hispanic activists — who were irate at the notion that Mr. Biden and Democrats would agree to severe border restrictions — to address their fears and anger.
Despite the all-out push, no agreement was ready before the Senate broke for Christmas, forcing Mr. Schumer and the negotiators to keep working over the holidays. He even made calls on Christmas Day, he said.
A promising moment came when Congress returned last month, Mr. Schumer said. Senator James Lankford of Oklahoma, the Republicans’ lead negotiator in the talks, began disclosing details of the potential agreement to top colleagues, who seemed to be impressed by how far Democrats had moved on the issue. Approval seemed possible, though in the weeks that followed, Mr. Trump began savaging the emerging deal pre-emptively and urging Republicans to reject it.
The deal quickly collapsed on Feb. 4, within hours of the details being made public. Far-right conservatives in the Senate rebelled, scoffing at the notion that Democrats had made real concessions and saying that Mr. Biden would not enforce the new law regardless.
Seeing the handwriting on the wall, Senate Republicans, including Mr. McConnell, ran from the agreement. Only four Republicans ended up voting to bring it to the floor. Republicans still intend to hammer Democrats on border security issues and blame the lack of tough border policy in the Ukraine aid bill as a rationale for not taking up the legislation in the House.
“The Senate’s foreign aid bill is silent on the most pressing issue facing our country,” Speaker Mike Johnson said in attacking the legislation and suggesting it was dead in the House.
Still, members of both parties credited Mr. Schumer for deftly playing a hand that insulated Democrats from a backlash to the collapse, provided a political defense on border policy and still allowed him and a bipartisan coalition of senators to salvage the Ukraine aid.
“He saw an opening, and he seized it,” said Senator Richard Blumenthal, Democrat of Connecticut. “His approach has kept this effort bipartisan despite the rancor and resistance.”
It also allowed Democrats wring maximum political benefit from the immigration debate without having to follow through with any policy concessions. They were able to signal to voters that they embraced strong border provisions — and blame Republicans for killing them — without having to put the restrictions into force, which would surely have alienated their progressive base.
But Mr. Schumer insisted he never rooted for the demise of the immigration package.
“It was a win-win either way,” he said, “but I would have preferred actual legislation, because the border is still going to be there.”