President Volodymyr Zelenskyy made a whirlwind return visit to Washington on Thursday to shore up U.S. support for Ukraine, delivering an upbeat message on the war's progress while facing new questions about the flow of American dollars that for 19 months has helped keep his troops in the fight against Russian forces.

Zelenskyy, in long-sleeve olive drab, came to the Capitol with a firm message in private talks with Republican and Democratic leaders. The Ukrainians have a solid war plan, and “they are winning,” lawmakers quoted him as assuring them, at a time that the world is watching Western support for Kyiv.

Zelenskyy received a warm welcome from both parties on his stop in the Senate. Minority Leader Mitch McConnell and Majority Leader Chuck Schumer flanked him as he walked in. A few lawmakers of both parties wore clothes with blue and yellow, the colors of the Ukrainian flag.

"There was a single sentence that summed it all up — and I’m quoting him verbatim," Schumer said of Zelenskyy: "'If we don't get the aid, we will lose the war.'"

House Republican leaders had promised tough questions for Zelenskyy on his plans for winning Ukraine's counteroffensive against invading Russian forces, as the war moves closer to the two-year mark and marks months without major breakthroughs in Russia's heavily mined lines.

“They need it, and they're gonna get it,” Texas Rep. Michael McCaul, who chairs the House Foreign Affairs Committee, told reporters. “The majority of the majority support this. I know there's some dissension on both sides."

Texas Sen. John Cornyn told reporters that Zelenskyy "made a good case" to lawmakers, but acknowledged that "some of the skeptics" in the Senate GOP conference "weren't there." 

Hawley, one of those skeptics on Ukraine aid who was in attendance, appeared to be unmoced by Zelenskyy's plea.

"His comment was, ‘It's a totally frozen conflict,'" the Missouri Republican told POLITICO. "I think his other comment was ‘Everything depends on the United States.’ Sounds more and more sort of like Vietnam in the day to me, if I’m going to be honest. So what he said was basically a recipe for just shy of needing to land American troops."

Zelensky “conceded that it’s tough, very tough to overcome entrenched defenses,” Maine Sen. Angus King, an independent who caucuses with Democrats, said. “They believe they will make slow but steady progress, but it’s not going to be quick.”

House Speaker Kevin McCarthy, who faces tough opposition on support for Ukraine among followers aligned with former President Donald Trump, notably chose not to join in greeting the Ukrainian president before the cameras. That left House Democratic leader Hakeem Jeffries to escort Zelenskyy into the Capitol.

But Republican Rep. Mike Turner, the chairman of the House Select Intelligence Committee, said Zelenskyy in his meeting with House lawmakers “gave us details on the offensive that were very positive and his long-term goals and objectives. People in the room appreciated and supported it.”

Speaking to reporters after the meeting, McCaul stressed lawmakers needed confidence that there was a clear strategy for victory.

“War of attrition is not going to win this,” McCaul said. “That’s what Putin wants," he said, referring to Russian President Vladimir Putin. "He wants to break the will of the American people and the Europeans.”

It is Zelenskyy's second visit to Washington since Russia invaded Ukraine in February 2022 and comes as President Joe Biden's request to Congress for an additional $24 billion for Ukraine’s military and humanitarian needs is hanging in the balance. Back home, Russian launched its heaviest strikes in a month in the hours before Zelenskyy’s arrival at Congress, killing three, igniting fires and damaging energy infrastructure as Russian missiles and artillery pounded cities across Ukraine.

National Security Council spokesman John Kirby called the Ukrainian president “our best messenger” in persuading U.S. lawmakers to keep vital U.S. money and weapons coming.

“It’s really important for members of Congress to be able to hear directly from the president about what he's facing in this counteroffensive," Kirby told reporters Wednesday, "and how he’s achieving his goals, and what he needs to continue to achieve those goals."

Biden has called on world leaders to stand strong with Ukraine, even as he faces domestic political divisions at home. A hard-right flank of Republicans, led by Trump, Biden’s chief rival in the 2024 race for the White House, is increasingly opposed to sending more money overseas.

Zelenskyy’s visit comes with U.S. and world government leaders watching as Ukrainian forces struggle to take back territory that Russia gained over the past year. Their progress in the next month or so before the rains come and the ground turns to mud could be critical to rousing additional global support over the winter. Russian President Putin, who believes he can outlast allied backing for Kyiv, will be ready to capitalize if he sees Ukraine is running low on air defense or other weapons

Since the start of the war, most members of Congress supported approving four rounds of aid to Ukraine, totaling about $113 billion, viewing defense of the country and its democracy as an imperative, especially when it comes to containing Putin. Some of that money went toward replenishing U.S. military equipment sent to the frontlines.

Democratic Sen. Mark Kelly of Arizona, who traveled to Kyiv this week, said cutting off U.S. aid during the Ukrainians’ counteroffensive would be “catastrophic” to their efforts.

“That would clearly be the opening that Putin is looking for,” Kelly said Wednesday. “They cannot be successful without our support.”

The political environment has shifted markedly since Zelenskyy addressed Congress last December on his first trip out of Ukraine since the war began. He was met with rapturous applause for his country’s bravery and surprisingly strong showing in the war.

His meeting with senators on Thursday took place behind closed doors in the Old Senate Chamber, a historic and intimate place of importance at the U.S. Capitol, signifying the respect the Senate is showing the foreign leader.

Zelenskyy also met with President Biden at the White House and spoke with military leaders at the Pentagon.

Rep. Steny Hoyer, Democrat of Maryland who attended the House meeting with Zelenskyy and lawmakers, said that McCarthy made no promises but that Republicans and Democrats were united in supporting Ukraine.

“I think the message was not necessarily a promise but a determination to make sure that we could help Ukraine win this war for freedom and for all of us,” he said.