WASHINGTON — President Biden and President Volodymyr Zelensky of Ukraine presented a united front against Vladimir V. Putin of Russia on Wednesday, even as Mr. Zelensky warned that his country was digging in for a long, cold winter of war and had little hope of securing a just peace with the “terrorists” who are battering his people.
“The longer the war lasts, the longer this aggression lasts, there will be more parents who live for the sake of vengeance, or revenge,” Mr. Zelensky said, standing at a podium next to Mr. Biden hours after leaving the front lines of his country’s war on a whirlwind diplomatic mission to Ukraine’s most powerful ally.
“So there can’t be any just peace in the war that was imposed on us,” he said, speaking in halting English instead of using a translator.
Mr. Zelensky arrived at the White House on Wednesday for a show of solidarity and to deliver a plea for even more economic and military support. The two men met behind closed doors for more than two hours before facing reporters to reaffirm their determination to defend Ukraine against Russian forces, who invaded in February.
Standing side by side in the East Room with Ukraine’s flag hanging next to gleaming Christmas decorations, Mr. Biden and Mr. Zelensky — in his wartime uniform of an olive green sweater and cargo pants — both pledged to continue fighting Russia’s invasion to force an end to Mr. Putin’s unwarranted aggression.
“The American people know that if we stand by in the face of such blatant attacks on liberty and democracy, and the core principles of sovereignty and territorial integrity, the world would surely face worse consequences,” Mr. Biden said.
“The American people have been with you every step of the way,” Mr. Biden told Mr. Zelensky. “And we will stay with you. We will stay with you for as long as it takes.”
But both leaders sounded grim about the prospects for an end to the conflict any time soon. Mr. Biden said it was critical to “stand together through 2023,” suggesting another year of war in the heart of Europe. Mr. Zelensky offered a blunt assessment of the months ahead: “We need to survive this winter,” he said. “We need to protect our people.”
Mr. Zelensky’s visit to Washington — kept secret until the eve of his arrival for security reasons — was a dramatic show of confidence by Ukraine’s leader, who had not left his country since Mr. Putin began his assault 300 days ago.
In the space of 24 hours, just days before Christmas, Mr. Zelensky flew from the battered front lines of a country plunged into darkness by Russian air attacks to the marble-lined rooms of the White House, where he repeatedly thanked Americans for being a “real partner” to Ukraine in its battle to survive.
The one-day trip to Washington was designed as a thank-you, a victory lap and a sales pitch all at once. Following the meeting with Mr. Biden, Mr. Zelensky was scheduled to deliver a speech to a joint session of Congress, where he was expected to say that his country could not survive without billions of dollars’ worth of sophisticated American war equipment.
Mr. Zelensky is certain to get some, but not all, of what he wants before he heads home, barely 10 hours after arriving in Washington.
Congress is just days away from approving almost $50 billion in additional security and economic assistance for Ukraine. Mr. Biden on Wednesday announced delivery of a Patriot missile battery to help Ukraine defend against attacks from the sky, but the administration is still refusing longer-range weapons that could strike deep into Russia and potentially draw the United States into direct conflict with Mr. Putin and his military.
Mr. Zelensky’s outstretched hand has rankled some Biden administration officials at times during the past year. Wednesday’s appearance at the White House offered a glimpse of the transactional nature of the relationship between two men as Mr. Zelensky acknowledged what he would do after receiving a Patriot missile battery from the United States to help defend Ukraine from air attacks.
“After that we will send another signal to President Biden that we would like to get more Patriots,” he said.
The aside underscored both the human dynamic at play between the two men and Mr. Biden’s fears that providing too much military assistance, too quickly, could unleash a broader conflict with Russia and the West that would have even more dangerous consequences.
Later, when a reporter from Ukraine asked Mr. Biden why he didn’t just give Mr. Zelensky all the weapons he wanted, Mr. Biden quipped: “His answer is yes,” pointing at the Ukrainian president.
“I agree!” Mr. Zelensky responded quickly, prompting laughter from the audience.
The visit to the White House comes as both sides gird for months of continued fighting. In Russia, officials warned that deliveries of new U.S. weapons would lead “to an aggravation of the conflict,” and Mr. Putin vowed that his government would provide “everything that the army asks for — everything” in its search for conquest.
“President Zelensky’s visit here is at least partially, maybe primarily, designed to bolster that support and rejuvenate the enthusiasm for Ukraine’s success,” said William B. Taylor Jr., who served as ambassador to Ukraine from 2006 to 2009. “That is all going to be necessary for the Ukrainians to be able to pre-empt a Russian offensive.”
“The timing is perfect,” he said.
For Mr. Biden, the highly orchestrated visit is an opportunity to remind Americans why he has committed the United States’ Treasury — though not its soldiers — to defending the borders of a country a continent away. It is critical, he argues, to stand up for the rights of sovereign nations when international law is violated.
That decision has not come without sacrifices and political cost for Mr. Biden, who rightly predicted before the war started that Americans would suffer economic consequences as the ramifications of the first war in Europe in decades rippled across the world. Gas and food prices spiked, helping to send inflation soaring in the United States and elsewhere.
Now, after rallying dozens of nations to oppose Russia’s invasion, Mr. Biden finds himself needing to hold that coalition together for longer than anyone inside the White House imagined at the start of the war. And he faces a concerted effort by Mr. Putin to break the alliance by restricting energy resources and attacking civilian areas in Ukraine.
“The most important part of this visit might be to combat Putin’s belief that time is on his side in the war,” said Richard Haass, president of the Council on Foreign Relations. “Putin can’t win in the battlefield so what he’s trying to do is break the will of the Ukrainian people by his attacks on civilian areas, and he’s trying to break Europe’s will by energy denial.”
Ahead of their meeting on Wednesday, Mr. Zelensky presented Mr. Biden with a cross for military merit, an award that he said was given to him by a soldier on the front lines in Ukraine. The soldier, a captain, said Mr. Zelensky should give it to the “very brave president” who had saved many lives in their country.
“Undeserved, but much appreciated,” Mr. Biden replied in a moment that underscored how the two leaders are intertwined in the ongoing conflict.
But Mr. Biden and Mr. Zelensky must continue to build support among Americans voters and lawmakers, some of whom have begun to have doubts about the wisdom of an open-ended commitment to a conflict that shows no signs of ending.
There remains widespread bipartisan support on Capitol Hill for financially supporting Ukraine in its war against Russia, and the majority of Republicans have rallied behind the aid. Some in the party have, however, pushed for greater oversight of the money being sent to Ukraine and others have questioned how much the country really needs.
Some Republican lawmakers in Congress have indicated that they will vote later this week against a $1.7 trillion government spending bill that includes the money for Ukraine. And Representative Kevin McCarthy of California, the Republican leader in the House, told reporters recently that “I’m not for a blank check for anything. This is hardworking taxpayer money. And I want to make sure whatever funding we spend goes to the right places.”
There is also evidence that Americans in both parties are growing weary of the ongoing conflict. Some Democrats have been hearing from constituents who question the routine infusions of aid and are pressing Biden administration officials to say how they think the conflict will end — and when.
Mr. Zelensky will have an opportunity to respond to those concerns during his speech to Congress on Wednesday evening. Senator Chuck Schumer of New York, the majority leader, said Mr. Zelensky’s appearance would be “a day to remember in the history of the United States Congress.” Senator Mitch McConnell of Kentucky, the minority leader, called Mr. Zelensky “an inspiring leader.”
During his remarks, Mr. Zelensky will have a chance to portray the war gripping his country in stark terms that he hopes will transcend domestic American politics. Aides to the Ukrainian president said he would speak about the American role in “strengthening resilience and defense” of his country.
“I think what Zelensky can do in his speech is make the case that Ukraine is essentially fighting for our interests and our values,” Mr. Haass said, adding that the Ukrainian president “has an opportunity to achieve a greater connection to the American people in support of Ukraine. It just hasn’t gained a lot of traction.”
Mr. Zelensky last spoke to members of Congress by video link in March, when he urged military aid and called the defense of Ukraine a battle for democracy itself. Speaking mostly in Ukrainian and wearing his trademark military-issue T-shirt, he told U.S. lawmakers they had a moral obligation to help.
“I call on you to do more,” he said, invoking Pearl Harbor and the Sept. 11 attacks, before making a plea for a no-fly zone, more weapons and for the United States to impose sanctions.
“Is this a lot to ask for, to create a no-fly zone over Ukraine, to save people? Is this too much to ask?” he said at the time.
Reporting was contributed by Emily Cochrane in Washington, Anton Troianovski in Berlin and Andrew E. Kramer in Kyiv.