WASHINGTON — All it took was 90 seconds for weeks of tortured diplomacy to unwind in spectacular fashion.

President Donald Trump's Oval Office thrashing of Ukraine's Volodymyr Zelenskyy on Friday laid bare the limits of a full-court press by America's allies aimed at reshaping Trump's determination to end Russia's invasion even if the terms are not to Ukraine's liking.

It also stressed the profound ways Trump feels emboldened to redirect U.S. foreign policy priorities toward his ''America First'' agenda in ways that extend well beyond those of his tumultuous first term.

The sudden blowup was the most heated public exchange of words between world leaders in the Oval Office in memory, as the usual staid work of diplomacy descended into finger-pointing, shouting and eye-rolling.

The encounter left the future of the U.S.-Ukraine relationship, and Kyiv's ability to defend itself in the brutal conflict with Russia, in mortal jeopardy.

''You either make a deal or we are out,'' Trump told Zelenskyy, underscoring the American leader's plans to dictate a swift end to the war or leave its longtime ally to continue the fight without its strongest backer.

Less than a day later, Zelenskyy used a series of posts on X to express his thanks to the American people, Trump and Congress for ''all the support," which he said Ukrainians ''have always appreciated," especially during the war.

''Our relationship with the American President is more than just two leaders; it's a historic and solid bond between our peoples. That's why I always begin with words of gratitude from our nation to the American nation,'' he added. Ukrainians want ''only strong relations with America, and I really hope we will have them,'' he said.

Zelenskyy was in London to meet with British Prime Minister Keir Starmer before a summit Sunday of European leaders.

Episode capped intense lobbying effort by American allies

The stunning episode in Washington had capped a week of what turned out to be largely futile efforts by U.S. allies to paper over differences between Washington and Kyiv and to try to steer Trump away from his flirtations with Moscow.

On Monday, French President Emmanuel Macron huddled with Trump to lay the groundwork for an eventual European-led peacekeeping force in Ukraine aimed at deterring future Russian aggression and to encourage the U.S. president to be more skeptical of Vladimir Putin.

But even as Trump and Macron greeted each other with a vise-like grip, the U.S. was splitting with its European allies at the United Nations by refusing to blame Russia for its invasion of Ukraine in a series of resolutions marking the third anniversary of the war.

On Thursday, British Prime Minister Keir Starmer visited Washington and appealed to Trump for a U.S. ''backstop'' for European nations who would provide front-line security for Ukraine. He was in essence looking for insurance that, should a peace deal be reached, Russia won't restart the fighting in the future. Starmer brought flattery and a state visit invitation from King Charles III to soften the ask.

The approach seemed to work, as Trump struck a more conciliatory tone toward Ukraine, calling America's support for the country against Russia's invasion ''a very worthy thing to do'' and disclaiming any memory that he had called the Ukrainian leader a ''dictator.''

But Trump also brushed aside Putin's past broken diplomatic promises, claiming they occurred under different presidents, and saying the Russian leader had never violated a commitment to him. It came as his aides were planning a series of negotiating sessions with Russian officials to lay the groundwork for a potential meeting between Trump and Putin in the coming weeks.

Mineral deal pursued by Trump goes by the wayside, for now

All the while, Trump was focused on securing a financial stake in Ukraine's critical minerals to recoup the tens of billions the U.S. has given to Kyiv to defend itself. Zelenskyy, meanwhile, wanted more than Washington's vague promises that the U.S. would work to preserve its economic interest in Ukraine under the agreement and pushed for more concrete security guarantees.

But Trump would not budge, and U.S. officials repeatedly said Zelenskyy would not be welcome to meet with the president to discuss Trump's push for negotiations with Russia until it was signed. After weeks of browbeating, Zelenskyy's government on Wednesday formally agreed to the proposal, clearing the path for Friday's meeting.

It started off cordially enough, as Trump and Zelenskyy spoke politely, even with admiration, of one of another for the first half-hour of the meeting. Trump even suggested he would continue some military assistance to Ukraine until he could secure an enduring peace deal with Russia.

But when the Ukrainian leader raised alarm about trusting any promises from Putin to end the fighting, Vice President JD Vance rebuked him for airing disagreements with Trump in public. It instantly shifted the tenor of the conversation. Zelenskyy grew defensive, and Trump and his vice president blasted him as ungrateful and ''disrespectful'' and issued stark warnings about future American support.

A warning before the meeting 'not to take the bait'

Sen. Lindsey Graham, R-S.C., a defense hawk and Trump ally, said he had warned Zelenskyy before the meeting ''not to take the bait'' in his dealings with Trump, who has repeatedly shown a penchant for throwing criticism but a deep resistance to receiving it.

It was Vance — a longtime critic of American support for Ukraine — who dangled it, when he insisted diplomacy was the only way forward.

''What kind of diplomacy, JD, you are speaking about?'' Zelenskyy said, listing Russia's past violations of ceasefires. ''What do you mean?''

''I'm talking about the kind of diplomacy that's going to end the destruction of your country,'' Vance responded before tearing into the Ukrainian leader. ''Mr. President, with respect, I think it's disrespectful for you to come into the Oval Office to try to litigate this in front of the American media.''

Trump then let loose, warning the Ukrainian leader, ''You're gambling with World War III, and what you're doing is very disrespectful to the country, this country that's backed you far more than a lot of people say they should have.''

At another point, Trump declared himself ''in the middle,'' seeming to formally break from years of American support for Ukraine. He went on to deride Zelenskyy's ''hatred'' for Putin as a roadblock to peace.

''You see the hatred he's got for Putin,'' Trump said. ''That's very tough for me to make a deal with that kind of hate.''

''It's going to be a very hard thing to do business like this,'' Trump said to Zelenskyy as the two leaders talked over each other.

Latest example of major shift in US foreign policy

The episode was just the latest instance of Trump's brazen moves to shift long-held American policy positions in his first six weeks back in office, portending even more uncertainty ahead for longtime American allies and partners who have already felt pressed to justify their place in Trump's eyes. It comes just weeks after Trump floated a permanent relocation of Palestinians in Gaza and an American takeover of the territory, and as he has doubled down on plans to put stiff tariffs on goods from Mexico and Canada starting next week.

After the Oval Office dustup, Zelenskyy was asked to leave the White House by top Trump advisers — scrapping plans for a lunch, a joint press conference and the signing of the economic agreement, even as the Ukrainian leader and his aides pushed for a ''reset'' on the meeting.

Trump later told reporters he didn't want to ''embolden'' the Ukrainian leader if he didn't want ''peace'' with Russia — flipping what Ukraine had seen as an inducement for security guarantees into a cudgel.

''You can't embolden somebody who does not have the cards,'' Trump said.

After the disastrous encounter, Zelenskyy appeared on Fox News on Friday evening and told Bret Baier that his public spat with Trump and Vance was ''not good for both sides.'' But Zelenskyy said Trump — who insists Putin is ready to end the three-year grinding war — needs to understand that Ukraine can't change its attitudes toward Russia on a dime.

Zelenskyy added that Ukraine won't enter peace talks with Russia until it has security guarantees against another offensive.

''Everybody (is) afraid Putin will come back tomorrow,'' Zelenskyy said. ''We want just and lasting peace.''

''It's so sensitive for our people,'' Zelenskyy said. ''And they just want to hear that America (is) on our side, that America will stay with us. Not with Russia, with us. That's it.''

Zelenskyy acknowledged that without U.S. support, his country's position would grow ''difficult.''

After repeatedly declining opportunities to apologize to Trump, Zelensky closed his Fox appearance with a sheepish expression of remorse as he struggled with the reality of Trump's new direction in Washington: ''Sorry for this."