For a former actor and comedian, it was the curtain call of a lifetime.

His address delivered, Volodymyr Zelenskiy walked up the centre aisle of the House of Representatives chamber to thunderous cheers, a standing ovation, eager handshakes and some members clamouring to touch him with almost religious reverence. One group had brought a giant Ukrainian flag. Others wore blue and yellow, the national colours.

They were last impressions to warm Zelenskiy as he flew back to bleak, wintry Ukraine. He could also reflect that he had written one more chapter in the strange, eventful history of America and Ukraine, two nations whose fates have become unexpectedly intertwined.

The 44-year-old president was making his first trip outside Ukraine since the Russian invasion in February. He was in Washington to thank Joe Biden, Congress and the American people for their support. The climax was his address to a joint session of Congress that included representatives, senators and members of Biden’s cabinet.

There was a rising hubbub of voices as the chamber awaited his entrance. Kevin McCarthy, running for speaker, gave someone an elaborate wink. Matt Gaetz offered a quip to Lauren Boebert, who chuckled. January 6 committee members Liz Cheney and Elaine Luria chatted then posed for a photo together.

It takes a lot to impress long-in-the-tooth politicians but the Time magazine person of the year’s combination of star quality and steel core was enough. As every member rose to their feet, applauding and hollering, even Zelenskiy was overwhelmed for a moment. “It’s too much for me,” he said.

He stood at the same spot that American presidents do when delivering the State of the Union address but cut a very different figure with short dark hair, a moustache and beard. The House waived a rule that requires men to wear a jacket and tie inside the chamber, allowing him to wear a sweater in his trademark wartime olive. He read his speech from pages placed on the lectern before him, tracing the words with his index finger as he spoke English in a raspy, accented voice.

“Against all odds and doom-and-gloom scenarios, Ukraine didn’t fall – Ukraine is alive and kicking,” he said, prompting one of many standing ovations.

More than one historian compared the visit to Winston Churchill sailing to America soon after the attack on Pearl Harbor. Churchill held a press conference with President Franklin Roosevelt and joined him in the ceremonial lighting of the National Christmas Tree. He also addressed Congress in the Senate chamber on 26 December 1941. At the end of his half-hour speech, the chief justice gave a “V” for victory sign and one reporter observed: “The effect was instantaneous, electric. The cheers swelled into a roar.”

Cheers turned to roars again for Zelenskiy when, in a nod to Churchill, he declared: “Ukraine holds its lines and will never surrender.”

He was also a polite guest, resisting the temptation to go all Oliver Twist and demand more. But he did remark: “Your money is not charity. It’s an investment in the global security and democracy that we handle in the most responsible way.”

He added: “Your support is crucial. We have artillery, yes. Thank you. We have it. Is it enough? Honestly, not really.” Some members of Congress burst out laughing, which would have been fine in Zelenskiy’s old job playing a fictional president of Ukraine on TV, but must have been less welcome as his people freeze.

America, of course, had its own celebrity turned president in the shape of Donald Trump. Whereas the Watergate rule was “follow the money”, the best advice in this era of American politics is “follow the ruble”.

Trump has made a habit of parroting the Kremlin’s talking points since a visit to Russia in 1987. Mysteriously, his campaign aides intervened during the 2016 Republican National Convention to block language from the Republican party platform that called on the US to send lethal arms to Ukraine.

The Russian president, Vladimir Putin, undoubtedly meddled in that year’s election. Special counsel Robert Mueller did not establish a conspiracy but the Trump campaign and transition team is known to have at least hundreds of known contacts and dozens of known meetings with Russia-linked operatives. Once he became president, Trump shied away from criticising Putin over anything.

Zelenskiy, already locked in a long conflict with Russia, had cause to wonder which side Washington was on. His face was a picture when Trump once told him: “I really hope that you and President Putin can get together and solve your problem.”

So it was hardly a surprise when, in 2019, the US president withheld nearly $400m in military aid from Ukraine in an effort to pressure Zelenskiy into announcing a bogus investigation into Biden and his family. This led to a congressional inquiry in which Ukraine was suddenly dominating media headlines and experts such as Fiona Hill were the talk of the town. Trump was ultimately impeached by the House but acquitted by the Senate.

When Joe Biden took office in 2021, Zelenskiy was not uppermost in his thoughts, but Russia’s invasion of the country in February this year changed all that. It gifted him an ‘Exhibit A’ in his oft-made argument that democracies face a struggle with autocracies for global preeminence. On his watch, the US has poured $20bn worth of military aid into Ukraine and is about send a battery of Patriot missiles.

In vivid contrast to Trump, the personal chemistry between Biden and Zelenskiy was palpable on Wednesday. At a joint press conference in the White House east room, Biden, at his most tactile, pointed to the Ukrainian and said: “This guy to his very soul is who he says he is. It’s clear who he is. He’s willing to give his life for his country and all the folks who came with him today.”

Zelenskiy, for his part, said through an interpreter: “As to what is the message for Putin, I am standing here in the United States with President Biden on the same podium because I respect him as a person, as a president, as a human being for his position. And for me, this is a historic moment.”

Zelenskiy expressed confidence that, despite the upcoming change in control of the House, America will stand firm in backing his cause. Despite some in the Trump wing questioning the cost, plenty of Republicans seemed to show enthusiasm on Wednesday night. They joined the cheering as, near the end of a half-hour speech, Zelenskiy presented Vice-president Kamala Harris and speaker Nancy Pelosi – probably presiding over their last joint meeting of Congress – with a Ukrainian flag signed by its soldiers. “We are united,” he said. “Ukraine, America and the entire free world.”

A decade ago few could have predicted that Ukraine would loom so large in Washington – in Donald Rumsfeld’s language, it was an unknown unknown. It would also have been hard to foresee that it would take a courageous leader from eastern Europe to bring Democrats and Republicans together. In the age of polarisation, unity at last. A sea of heads turned upwards as a Ukrainian contingent in the public balcony shouted: “God bless America! Thank you, thank you, thank you.”