WASHINGTON — His country’s future at stake, Ukrainian President Volodymyr Zelenskyy used inspirational words, optimistic resolve and a nod to Christmas in appealing Tuesday to leaders in Congress for U.S. aid for his fighters in the war with Russia.

But after hours of talks on Capitol Hill, additional American support appeared in grave doubt as Zelenskyy arrived at the White House to huddle with President Joe Biden. The U.S. has already provided Ukraine $111 billion since Russian President Vladimir Putin launched his grinding invasion more than 21 months ago, but Republicans are insisting on linking any more money to strict U.S.-Mexico border security changes that Democrats decry.

The White House is warning that if new money isn’t provided by year’s end it will have swift consequences for Ukraine’s capacity to hold its territory, let alone take back land captured by Russia.

Biden, speaking at an early evening news conference with Zelenskyy, warned that failure by the United States to provide Ukraine further aid would embolden Putin and other aggressors on the world stage.

“Putin is banking on the United States failing to deliver on Ukraine,” Biden said. “We must, we must, we must prove him wrong.”

Earlier meeting with Zelenskyy in the Oval Office, Biden called on Congress “to do the right thing, to stand with Ukraine, and to stand up for freedom.” He added, “Congress needs to pass the supplemental funding for Ukraine before they break for the holiday recess. before they give Putin the greatest Christmas gift they could possibly give him.”

Zelenskyy made his own case during his brief White House appearance with Biden and his private meetings with congressional leaders — that Ukrainian forces have fought fiercely to push back the Russian invasion with the help of American and other Western allies and it’s no time for Ukraine’s friends to step back.

“The fight we’re in is a fight for freedom,” Zelenskyy repeatedly said in the meetings on Capitol Hill, according to lawmakers.

Meanwhile, more than 130 senior lawmakers from across Europe signed a letter urging U.S. lawmakers to continue their support for Ukraine.

Flanked by Democratic Majority Leader Chuck Schumer and Republican Minority Leader Mitch McConnell, Zelenskyy entered a private meeting with senators with a public bipartisan show of support and to some applause. But more than an hour later few senators’ minds appeared changed.

Zelenskyy also visited the House leaders, including privately with new Speaker Mike Johnson, whose hard-right Republicans have been the most resistance to any deal. Johnson insisted afterward: “We do want to do the right thing here.”

Zelenskyy sought to impress on the senators that Ukraine could win the war against Russia, telling them he was drafting men in their 30s and 40s in a show of strength for the battle. In his trademark olive drab, he stood before a portrait of George Washington, history hanging behind him.

To the House Democrats, he showcased his country’s embrace of the West by pointing to the Christmas season, telling them it was the first year Ukraine would celebrate on Dec. 25 rather than the day Russians mark the holiday.

McConnell said Zelenskyy was “inspirational and determined” in the Senate meeting.

But Republican senators exited the meeting unmoved from their position. Sen. Markwayne Mullin of Oklahoma said the emergency funding wouldn’t gain GOP support unless it includes “real, meaningful border reform.”

Biden pushed back that “history will judge harshly those who turned their backs on freedom’s cause.” The president quoted a Kremlin-aligned television host celebrating Republicans’ recent blocking of aid as a job “well done.”

“If you’re being celebrated by Russian propagandists, it might be time to rethink what you’re doing,” Biden said.

Biden has been calling for a $110 billion U.S. aid package for Ukraine, Israel and other national security needs.

He has expressed a willingness to engage with the Republicans as migrant crossings have hit record highs along the U.S.-Mexico border, but Democrats in his own party oppose proposals for expedited deportations and strict asylum standards as a return to Trump-era hostility towards migrants. Homeland Secretary Alejandro Mayorkas visited the Capitol to help with talks, but was not expected to be negotiating any deal.

One chief Republican negotiator, Sen. James Lankford of Oklahoma, said there was nothing Zelenskyy could say during his visit with the senators to sway the outcome.

“Hey, pay attention to us, but not your own country? No,” Lankford told reporters.

Ahead of Zelenskyy’s high-stakes meetings, the White House late Monday pointed to newly declassified intelligence that shows Ukraine has inflicted heavy losses on Russia in recent fighting along the Avdiivka-Novopavlivka axis — including 13,000 casualties and over 220 combat vehicle losses. The Ukrainian holdout in the country’s partly-occupied east has been the center of some of the fiercest fighting in recent weeks.

U.S. intelligence officials have determined that the Russians think if they can achieve a military deadlock through the winter it will drain Western support for Ukraine and ultimately give Russia the advantage, despite the fact that Russians have sustained heavy losses and have been slowed by persistent shortages of trained personnel, munitions and equipment.