Inside the Oval Office fight that could decide the future of Ukraine

It had been a relatively polite Oval Office meeting between Trump and Ukrainian President Volodymyr Zelensky, who was in Washington on a mission to secure the U.S.’s continued support in the effort to end Russia’s three-year-old war.

But Vice President JD Vance interjected. “I have to respond," he said, taking issue with reporters’ questions about Trump’s interactions with Russian President Vladimir Putin. “What makes America a good country is America engaging in diplomacy. That’s what President Trump is doing," Vance said.

Zelensky shot back, laying out Putin’s yearslong campaign to occupy Ukraine.

From there, the conversation devolved into a tense and personal argument that played out on television cameras in front of millions of viewers, stunning senior officials in Washington and Kyiv and threatening a U.S.-Ukraine deal that could have laid a pathway for ending the war.

It ended with Trump declaring that the beleaguered nation didn’t want his help reaching a ceasefire—and the U.S. president kicking Zelensky out of the White House, according to American and Ukrainian officials.

It was also a rare moment of public tension in the Oval Office, which has for years been the staging ground for tightly choreographed interactions between U.S. presidents and world leaders.

“I think it’s disrespectful to come to the Oval Office and try to litigate this in front of the American media," a visibly angry Vance said, before continuing to chide the Ukrainian leader.

“Have you said thank you once?" Vance asked. “We are thankful," Zelensky responded.

At one point, Zelensky accused Vance of shouting, saying: “You think that if you will speak very loudly —" but Trump interrupted, saying “He’s not speaking loudly. Your country is in big trouble."

“I know," Zelensky said.

“You’re not winning," Trump said. “You’re not winning this. You have a damn good chance of coming out OK, because of us."

The U.S. president, hunched over in his chair between Zelensky and Vance, pointed his finger at the Ukrainian leader as he spoke and at one point touched Zelensky’s shoulder.

The long-planned meeting was the culmination of a week of discussions with European leaders, who spent days flattering the U.S. president in hopes that he would come to Ukraine’s aid.

For days, Trump telegraphed that Zelensky would sign a rare minerals deal that would eventually reimburse the U.S. for the billions that it has sent to Kyiv. Instead, it ended with a canceled press conference and Zelensky leaving the White House early.

As the Oval Office standoff unfolded, Ukrainian Ambassador Oksana Markarova stopped scribbling in a blue notebook and put her head in her hands. A White House staffer whispered, “this is going to be big."

After the media left the Oval Office, word circulated in the crowded White House press room that the rest of the day’s scheduled events with Zelensky would be called off. Television cameras and reporters gathered outside the White House to watch Zelensky’s black SUV depart.

When world leaders come to the U.S. to meet with the president, they typically sit in the Oval Office and exchange rehearsed comments about one another with the media present. Then they close the doors and hash out their differences.

That’s what happened this week when Trump met with French President Emmanuel Macron and UK’s Prime Minister Keir Starmer. The schedule for Friday was similar, until it went off the rails.

The disagreements between Trump and Zelensky started to emerge as the two men took a series of questions from reporters that centered on whether Russian President Putin can be trusted. Trump said that he has a particularly close relationship with Putin and suggested that their bond grew in his first term after Russia was accused of meddling in the election on his behalf.But as Trump suggested that Putin would honor agreements, Zelensky shook his head in disagreement.

Earlier in the meeting, a reporter asked Zelensky why he wasn’t wearing a suit. Zelensky has a tradition of wearing casual, military-style clothing with world leaders as a visual reminder to the world that his country is at war. He said that when his country isn’t at war, he will wear a nice suit, perhaps nicer than the blue one the reporter was wearing.

Secretary of State Marco Rubio, sitting on a sofa, frowned and looked away as Vance laughed at the question.

Still, Trump and Zelensky seemed to largely paper over their disagreements at first, with Zelensky initially only lightly reminding the Americans about his extensive experience dealing with Putin and the many times that the Russians haven’t honored agreements.

Then Vance said he wanted to respond to the question that Trump had just answered on whether the president is aligned with Russia. Trump had said he was aligned with the world, wanting to find peace.

Trump initially watched as the two men bickered back and forth. But he cut in when Zelensky said that the U.S. would eventually feel the consequences of trusting Russia, suggesting that Putin won’t be satisfied.

“You’re in no position to dictate to us what we’re going to feel," Trump said, later adding: “you’re gambling with World War III."

After about 50 minutes, Trump said “I think we’ve seen enough" signaling to his press staff to ask the media to leave. As reporters left the Oval Office, Trump quipped, “This is going to be great television."

Write to Annie Linskey at annie.linskey@wsj.com and Natalie Andrews at natalie.andrews@wsj.com