Vladimir Putin, the president of Russia, has managed to do what Joe Biden could not: bridge the partisan divide and bring, however fleetingly, the US Congress together.

Many Democrats and Republicans who attended the US president’s first State of the Union address, on Tuesday night, wore yellow and blue in solidarity with Ukraine, with some holding miniature Ukrainian flags.

And when Biden discussed the world-shaking events of the past week – this will inevitably be remembered as his Ukraine speech, irrespective of inflation and other domestic concerns – the chamber rose as one to applaud time and again.

Putin “thought he could divide us at home in this chamber and this nation”, said Biden, wearing a dark suit, white shirt and blue tie. “He thought he could divide us in Europe as well. But Putin was wrong. We are ready, we are united and that’s what we did: we stayed united.”

It was not a subject that Biden expected or wanted to be talking about even a few weeks ago. The man who gives a portrait of President Franklin D Roosevelt pride of place in the Oval Office now finds himself pivoting from New Deal FDR to wartime FDR, from sweeping economic reforms to facing down an unhinged European despot.

Russia’s unprovoked attack on Ukraine meant that Biden’s 62-minute speech was addressing not only the chamber on Capitol Hill and the nation but the world, even as bombs fell on Ukrainian cities. Some in Europe remain frustrated that the US has not done more to cow Putin. The president found himself cast in the role of what some still quaintly call “leader of the free world”.

“We are inflicting pain on Russia and supporting the people of Ukraine,” Biden said of withering sanctions. “Putin is now isolated from the world more than ever.”

He promised to defend “every inch” of Nato territory.

But Biden being Biden, infamous for his gaffes, all did not go smoothly. In a slip of the tongue, he said Putin would never gain the hearts and souls of the “Iranian” people when he meant Ukrainian.

Curiously and ominously, the 79-year-old deviated from his prepared remarks to ad lib: “He has no idea what’s coming,” and finished the speech with a clenched fist and: “Go get him!”

With Russia’s nuclear deterrent forces on high alert, this was no time for a repeat of President Ronald Reagan’s “We begin bombing in five minutes” quip.

But Uncle Joe is stronger when it comes to bedside manner. There was a grace note of reassurance for Americans who have genuinely been discussing the possibility of a third world war. “I know the news about what’s happening can seem alarming to all Americans,” he said.

“But I want you to know, we’re going to be OK, we’re going to be OK. When the history of this era is written, Putin’s war on Ukraine will have left Russia weaker and the rest of the world stronger,” said Biden to a standing ovation.

Democrats and Republicans united in approval of Biden’s plan to close American airspace to all Russian flights and build a dedicated taskforce to go after the crimes of oligarchs. “We are joining with our European allies to find and seize your yachts, your luxury apartments, your private jets. We are coming for your ill-begotten gains.”

They united again in a tide of emotion as Oksana Markarova, the Ukrainan ambassador to the US, stood in the public gallery, whispering “thank you” with tears in her eyes, right hand on heart, left hand clutching a mini flag. Markarova was a guest of the first lady, Jill Biden, and travelled in the presidential motorcade from the White House to Capitol Hill.

For a moment it was the 20th century again, when partisan differences seemed small compared to the external, existential threat of the Soviet Union. There is nothing so unifying as a common foe.

Then came a jarring gear shift. When Biden moved to the domestic area, and took a swipe at the Donald Trump administration’s tax cuts for the rich, Republicans erupted in booing. For a moment, it was almost a surprise, but then not really: the bloodsport of daily politics had resumed.

So it was that later, when Biden talked about security at the US-Mexico border, two far-right Republican House members, Lauren Boebert and Marjorie Taylor Greene, shouted “Build the wall!” as if trying to conjure Trump’s ghost from the depths. A Democrat snapped: “Sit down.”

And when Biden made reference to flag-draped coffins returning from Afghanistan, Boebert heckled: “You put them in, 13 of them!” – a reference to the 13 US personnel who died during the evacuation. Democrats booed loudly in response.

But when Biden spoke of crime and declared: “The answer is not to defund the police,” both sides united in cheering again while Congresswoman Alexandria Ocasio-Cortez laughed rather than clapped and her fellow progressive Ilhan Omar sat stony-faced.

The president’s Build Back Better agenda has stalled but he pushed some of its components. Likewise he warned that voting rights were “under assault”. His nemesis on both counts, the Democratic Senator Joe Manchin of West Virginia, sat between the Republicans Mitt Romney and Roger Wicker in an extravagant gesture of bipartisanship unlikely to charm liberals.

It was another sign that the more things change, the more they stay the same in the theatre of the State of the Union. For the first time in its history, two women – Vice-President Kamala Harris and House Speaker Nancy Pelosi – sat behind the president.

As members of Congress from each side cheered or jeered each punchline, five supreme court justices and military men worked hard to remain still and expressionless.

Senators and representatives were physically distanced on the floor and in the public gallery but face masks were gone – a hopeful sign of time healing all. “Let’s use this moment to reset,” Biden pleaded. “Let’s stop looking at Covid-19 as a partisan dividing line and see it for what it is: a God-awful disease. Let’s stop seeing each other as enemies, and start seeing each other for who we really are: fellow Americans.”

Putin, not Biden, might achieve that end. The president’s approval rating is dismal and there is no guarantee this primetime address will do anything to arrest the decline.

Was it a speech for the ages, with a ringing phrase that will define this moment of global peril? Perhaps not. But it will have made millions of people in America and around the world grateful that the man at the podium was not Donald Trump.