Presiding over his first State of the Union address as speaker of the House, Mike Johnson sat at center stage, just over President Biden’s left shoulder, with one of the worst poker faces in American politics.

His eyebrows arched and fell. He pursed his lips. He couldn’t decide whether he should stand up, smile or frown.

He smirked. He corrected himself. He sort of rolled his eyes. He looked down. He sighed. He shook his head. He swallowed. He smiled again. He looked amused and patient when he clearly intended to look serious and not pleased at all.

To be fair, another performer had seemed to miss his own cue first.

As is customary, Mr. Johnson banged the gavel when Mr. Biden stepped up to the rostrum. And when Mr. Biden began, “Mr. Speaker,” Mr. Johnson briefly leaned forward, as if expecting Mr. Biden to give him the opportunity to deliver the ceremonial introduction of the president.

Instead, Mr. Biden launched right into his speech, and Mr. Johnson nodded politely and took his seat.

He then had the high privilege and distinct honor of trying to control his boyish facial expressions for more than 70 minutes on national television.

“I am afraid he may have practiced it in front of a mirror,” said the presidential historian Douglas Brinkley.

Mr. Johnson had urged his fellow Republicans, ahead of the speech, to respect the decorum of the event, and to refrain from the disruptions that have become commonplace in recent years. He more or less succeeded at keeping his party under control.

But his own brows, lips and eyes were another matter.

Part of Mr. Johnson’s challenge was one of contrast. Seated to his right, Vice President Kamala Harris managed to appear both relaxed and disciplined, her face always on message.

As long as there have been cameras trained on presidents, House speakers have been more than just State of the Union scenery. They are often silent characters — particularly when they belong to the president’s opposition.

Paul Ryan joked that he practiced his own poker face for former President Barack Obama’s final State of the Union, Mr. Ryan’s first as speaker.

Nancy Pelosi was a foil for former President Donald J. Trump, alternating a sarcastic clap with an unflinching scowl. At the end of Mr. Trump’s 2020 address, she calmly stood up and tore his printed remarks in half, like a dissatisfied customer rejecting a bill.

And Thomas P. O’Neill Jr., in 1984, could be seen over Ronald Reagan’s left shoulder, leaning backward, rolling his papers into a tight tube, which he put down only to applaud.

Mr. Johnson did not touch the papers in front of him, and while he sometimes nodded in approval, he appeared to applaud Mr. Biden only sparingly — most notably, after Mr. Biden said no American soldiers would be on the ground in Ukraine, and when Mr. Biden quoted Reagan.

While Ms. Harris rose frequently to join standing ovations by her fellow Democrats, Mr. Johnson got no such exercise.

Still, at the end of the speech, Mr. Johnson both applauded and rose to his feet, shook the president’s hand, buttoned his suit jacket, and — as Mr. Biden lingered in the well of the House chamber — looked very ready to go home.

The state of the union as President Biden appeared before a divided Congress on Thursday night was rowdy.

Mr. Biden delivered a feisty, shouty, confrontational speech. Republicans jeered when he challenged them on immigration and economic matters, and he appeared to relish and even encourage the unscripted back and forth as he made his formal address on Capitol Hill.

Democrats cheered loudly and often in support of his policies, giving the impression of a party fully behind — and even excited about — its aged presidential nominee. The only glimmers of Democratic dissent came from a few progressives who sat stone-faced and held up signs demanding a lasting cease-fire between Israel and Hamas during portions of the speech.

It all unfolded as former Representative George Santos of New York, the serial fabulist who was expelled from Congress by his own colleagues in December, made a splashy return to the House floor that he had vowed only months ago to never visit again. Mr. Santos, dressed in a crystal-encrusted collar and sparkling shoes, even made his own news during Mr. Biden’s speech. He announced on social media that he planned to make another run for Congress, this time from New York’s First Congressional District.

It was, in short, a raucous night for a typically staid Washington tradition.

Speaker Mike Johnson, presiding over his first State of the Union since his improbable elevation last fall, could not seem to decide what to do with his face, alternating between pursing his lips, smiling, frowning, arching his eyebrows and shaking his head ruefully as the president spoke.

Some Republicans sat in the chamber looking and acting as if they were attending a rally for former President Donald J. Trump rather than a joint session of Congress. Representative Troy Nehls, the Texas Republican who earlier this year floated the idea of electing Mr. Trump as speaker, came wearing a T-shirt decorated with Mr. Trump’s mug shot.

As he made his way to the rostrum, Mr. Biden gasped and appeared taken aback by Representative Marjorie Taylor Greene, the hard-right Republican from Georgia, who had dressed herself as a one-woman political protest. She wore a red “Make America Great Again” cap and a T-shirt emblazoned with the name of Laken Riley, the 22-year-old nursing student allegedly killed by a Venezuelan migrant, a horror story Republicans have used as a cudgel against Mr. Biden.

“It’s about Laken Riley!” she cried out later from her seat during the segment of Mr. Biden’s speech devoted to the U.S. border with Mexico, in which Mr. Biden blamed his “predecessor” (as he referred to Mr. Trump all night) for tanking a bipartisan border security bill.

Ms. Greene saw her moment, interrupting the president to call the suspect in Ms. Riley’s killing an “illegal.” The authorities have charged a Venezuelan migrant who crossed into the United States illegally and was then released on parole. “Say her name!” Ms. Greene shouted.

In response, Mr. Biden did, in fact, say her name, albeit botching the pronunciation so it sounded more like “Lincoln Riley.” The president referred to her as “an innocent young woman who was killed by an illegal — that’s right.”

“But how many of thousands of people are being killed by legals?” he said.

(For years, studies have found that undocumented immigrants have much lower crime rates than citizens born in the United States and legal immigrants across a variety of offenses, including violent crimes, drug crimes and property crimes.)

He added: “To her parents, I say, my heart goes out to you. Having lost children myself, I understand.”

The president’s off-script use of the term “illegal” drew immediate pushback from progressives. “No human being is illegal,” Representative Delia Ramirez, Democrat of Illinois, posted on social media shortly after he uttered the word.

Still, the jousting with Republican critics appeared to energize Mr. Biden and the Democrats sitting in the audience.

From their chants of “four more years!” as Mr. Biden made his way into the chamber, to the constant exclamations of “that’s right!” that punctuated his speech, Democrats were quick to their feet for applause lines and cheered wildly for the leader of their party.

There were a few exceptions. Representatives Rashida Tlaib of Michigan, Cori Bush of Missouri and Ayanna Pressley of Massachusetts held up signs that said “lasting cease-fire now” and “stop sending bombs” while Mr. Biden discussed the war in Israel.

“More than 30,000 Palestinians have been killed, most of whom are not Hamas,” he said. “Thousands and thousands of innocents, women and children. Girls and boys also orphaned. Nearly two million more Palestinians under bombardment or displacement.”

As Mr. Biden ticked through the wreckage in Gaza, Ms. Tlaib, the only Palestinian-born member of Congress, wiped tears from her eyes and was comforted by her colleagues.

On the other side of the chamber, Mr. Santos was greeted more warmly than he ever had been when he was a member of Congress, back when his colleagues wanted nothing to do with him. Before the speech, he sat and chuckled with Representatives Lauren Boebert of Colorado and Matt Gaetz of Florida. Even members who had publicly criticized him in the past, like Representative Claudia Tenney of New York, stopped to snap his picture, while others made a beeline to greet him.

It was fair to say that Mr. Santos, who is scheduled to go on trial in September on federal fraud charges that include accusations of stealing money from campaign donors for personal expenses, was holding court.

He appeared to be staking out a seat near the corridor where Mr. Biden was set to enter the chamber, positioning himself to be close enough to reach out for a presidential handshake. But minutes before Mr. Biden’s entrance, without a seat saved, Mr. Santos moved himself to the back and out of sight.

It was Mr. Biden who stayed in sight until the bitter end. Long after he had finished speaking, and after most lawmakers, cabinet secretaries and Supreme Court justices had cleared out of the chamber, the president closed down the joint, sticking around with a few stragglers to shake hands and chat for close to 30 minutes more.

“You fired us all up!” Representative Danny K. Davis, Democrat of Illinois, told him.

President Biden delivered the speech. He survived the speech. He had some jokes, got some laughs and provided some rousing economic commentary about the availability of Snickers bars and potato chips.

Then came the fun part.

“No one’s going to talk about cognitive impairment now!” Representative Jerrold Nadler, Democrat of New York, told the president after the speech, referring to all the concern about Mr. Biden’s age and his ability to handle the demands of the job.

“I kind of wish sometimes I was cognitively impaired,” replied Mr. Biden, perhaps talking about the speech he had just delivered. Or the stress of his job. Or House Republicans.

For at least 25 minutes after completing his State of the Union address on Thursday, Mr. Biden lingered with well-wishers who had gathered to praise a speech that had been energetic and more political than in previous years.

The president seemed happy he was done with his high-wire act, and for a while it looked like he would never leave. Speaker Mike Johnson and Vice President Kamala Harris chatted idly behind Mr. Biden as he circulated.

Finally, a House protocol officer told Mr. Biden that many in the chamber could not leave until he did.

“Are they Democrats or Republicans?” the president joked back, according to a reporter who saw the interaction.

Eventually, Mr. Johnson gaveled the session closed even with Mr. Biden still in the chamber.

The moment was a homecoming of sorts for Mr. Biden, who spent 36 years commuting to Capitol Hill as a Democratic senator from Delaware. He seemed eager for the praise. Before the speech, his allies had said he was craving interaction with people outside the gilded cage of the White House.

“As president, he doesn’t ever get the chance to just stop by and just engage with people,” Senator Chris Coons, Democrat of Delaware and an ally of Mr. Biden’s, said in an interview this week. The presidency, Mr. Coons said, had “made it harder than ever for him to just connect with people casually.”

Which is precisely what Mr. Biden did as the House chamber emptied and he stayed behind. He shook hands with some House members, including Representative Pramila Jayapal, Democrat of Washington and the chairwoman of the Congressional Progressive Caucus.

“I need you to bring that energy that you brought tonight,” Representative Nikema Williams, Democrat of Georgia, told him.

“I have too much energy,” the president replied. “That’s the problem.”

Finally, almost a half-hour after the speech ended, Mr. Biden departed a mostly empty chamber and headed home. He spent some time at the White House greeting supporters before finally going inside just before midnight.

Two years ago, just six days after the Russian invasion of Ukraine, President Biden opened his State of the Union address by vowing to stop Vladimir V. Putin in his tracks. The response in the House chamber was a series of standing ovations.

On Thursday night Mr. Biden again opened his address by repeating his warning that, if not stopped, Mr. Putin would not halt his territorial ambitions at Ukraine’s borders. But the political environment was completely different.

With many Republicans vowing not to vote for more aid and Ukrainians running short of ammunition and losing ground, Mr. Biden challenged them to defend former President Donald J. Trump’s declaration that if a NATO country failed to pay enough for its defense, he would tell Mr. Putin to “do whatever the hell you want.”

While Democrats cheered at Mr. Biden’s direct shot at his opponent in the 2024 election, many Republicans in the chamber looked down or checked their phones — an illustration of the shifting and multiplying challenges he faces at a moment when his foreign policy agenda is playing a central role in the re-election campaign.

Mr. Biden’s vow to restore American power by rebuilding alliances and to “prove democracy works” is a far more complicated task than it was when he came into office.

His problems run deeper than the new thinking of a Republican Party that has moved in 20 years from President George W. Bush’s declaration that America’s mission would be the spread of democracy to Mr. Trump’s open admiration of Mr. Putin and quasi-autocrats like President Viktor Orban of Hungary, who is visiting Mar-a-Lago on Friday.

On the progressive side of his own party, Mr. Biden has been stunned to discover that a whole generation of Americans do not share his instinct to protect Israel at all costs, and are deeply critical of how he let American weapons fuel Prime Minister Benjamin Netanyahu’s continued bombing of civilian areas of Gaza, where more than 30,000 people have died, according to local health authorities.

After two Democratic primaries in which “uncommitted” won notable percentages of the vote in a protest of the administration’s Mideast policy, Mr. Biden spent the latter part of his speech scrambling to let progressives know he was listening. He described in detail what Gazans have gone through and insisted that “Israel must allow more humanitarian aid.” It was a change of tone for a president who has been loath to pressure Mr. Netanyahu in public, even as the two leaders have argued bitterly over secure lines.

Mr. Biden tried to use the receding memory of the Jan. 6, 2021, attack on the Capitol to sew his domestic and foreign democracy agenda together, at one point declaring that the rampage “posed the greatest threat to democracy since the Civil War.”

And while he was counting on the sound of booing that he knew would greet those remarks, hoping it would expose the election deniers in Congress and beyond, the sound was almost certain to be heard from Beijing to Berlin, where leaders are desperate to gauge which America they will be dealing with in 10 months’ time.

Ukraine poses the clearest test of Mr. Biden’s ability to declare that he rebuilt American alliances just in time.

He opened by recalling Franklin D. Roosevelt’s State of the Union address in 1941, when “Hitler was on the march” and “war was raging in Europe.” He compared that moment to today, arguing that “if anybody in this room thinks Putin will stop at Ukraine, I assure you, he will not.”

It was part of a strategy to cast the opponents of future military assistance to Ukraine as appeasers, accusing Mr. Trump — whose name he never uttered, calling him “my predecessor” — of “bowing down to a Russian leader.” And he went on to celebrate NATO, “the strongest military alliance the world has ever known.’’

Now, after two years in which the alliance has rediscovered its mission — containing Russian power — even that line left Republicans silent. Nothing that has happened in the past two years, even the European commitment of $54 billion to rebuild Ukraine and the provision of Leopard tanks and Storm Shadow missiles and millions of artillery rounds, has thrown Mr. Trump off his talking points. He still denounces the alliance as a drain on America, and his former top aides say that, if elected, he really might withdraw from the alliance.

Mr. Biden’s most influential advisers, including Senator Chris Coons, the Delaware Democrat who talks with the president frequently, have maintained that casting Mr. Trump as sympathetic to the Russian leader is the rare case of a foreign policy issue that could move the needle of a presidential election.

And they think support for Ukraine runs deeper than it looks. Many Democrats contend that if the bill to give $60.1 billion in additional aid to Ukraine — much of which will stay in U.S. weapons factories — received a clean up-or-down vote in the House, it would pass. But under pressure from Mr. Trump, Speaker Mike Johnson has so far kept the vote from coming to the floor.

But if Ukraine is a place of moral clarity for Mr. Biden and his argument that American intervention on behalf of democracies is at the core of the national mission, the Israel-Hamas war is a morass.

Mr. Biden’s announcement during the State of the Union address that he had ordered the military to funnel emergency aid into Gaza by building a pop-up port on the Mediterranean Sea was on one level a demonstration of America’s global reach, as it struggles to stem a massive humanitarian disaster before hundreds of thousands starve.

But in other ways it was also a symbol of Mr. Biden’s global frustrations.

The very fact that he had to order the construction of the floating pier in Israel’s backyard, apparently without its help, was a remarkable acknowledgment of how his repeated entreaties to Mr. Netanyahu have fallen on deaf ears.

Unable to sway Mr. Netanyahu and his war cabinet, Mr. Biden is quite literally routing around them, building floating piers that were designed for going ashore in hostile territory. Biden’s order was driven not only by humanitarian impulse, but also by the electoral necessity of knitting together his party’s divides over Middle East policy and demonstrating that he is prepared to do far more for the Palestinians than Mr. Trump is.

“To the leadership of Israel I say this,” Mr. Biden said on Thursday. “Humanitarian assistance cannot be a secondary consideration or a bargaining chip. Protecting and saving innocent lives has to be a priority.”

Mr. Biden is not yet where the left of his party is; he did not, for example, say that he would put restrictions on how American arms provided to Israel can be used. And while the new maritime effort to rush in aid may help, if combined with a pause or cease-fire that allows the distribution of food and medicine, Mr. Biden may be too late for the purposes of recovering disenchanted members of his base.

Remarkably, the foreign policy initiative that Mr. Biden regards as the single most important in his term got the least mention: containing China’s power, while competing with it on key technologies and urging it to cooperate on climate and other common issues.

He gave China a mere seven lines, yet officials say it remains at the core of his strategy. But even there, he could not resist a jab at Mr. Trump, who during the pandemic railed against the “China virus” but was slow to cut off chips and chip-making equipment, as Mr. Biden has. “Frankly, for all his tough talk on China,” Mr. Biden said, “it never occurred to my predecessor to do that.”

This was not Old Man Joe. This was Forceful Joe. This was Angry Joe. This was Loud Joe. This was Game-On Joe.

In an in-your-face election-year State of the Union address, President Biden delivered one of the most confrontational speeches that any president has offered from the House rostrum, met by equally fractious heckling from his Republican opponents.

It was an extraordinary spectacle that exemplified the raucous nature of modern American politics, one that made clear how far Washington has traveled from the days of decorous presidential addresses aimed at the history books. Mr. Biden again and again assailed his opponent in the fall election and the opposition lawmakers sitting in front of him. Republicans jeered and booed. Democrats chanted, “Four more years,” as if it were a campaign rally.

But that was the point. Frustrated by all the talk about his age and determined to dispel voter doubts, Mr. Biden, 81, used the most prominent platform of this election year, with what is likely the largest television and internet audience he will address before November, to exhibit his stamina, his vitality, his capacity and, yes, his umbrage. Defiant and feisty, he dispensed with the conventions of the format to directly take on former President Donald J. Trump and attempted to make the election a referendum on his predecessor rather than himself.

While he did not use Mr. Trump’s name, Mr. Biden referred to “my predecessor” 13 times and unabashedly denounced “you in this chamber” for being the former president’s lackeys by blocking security aid to Ukraine and a bipartisan border deal for political reasons. Every time they hooted or interrupted, he gave as good as he got, mocking their points and challenging them to pass important legislation.

He was so pumped up, so eager to get started, that he rolled right over House Speaker Mike Johnson, opening his speech without letting the neophyte Republican leader make the traditional “high privilege and distinct honor” introduction. Mr. Biden shouted his lines, clearly intending to use volume to demonstrate vigor. The prepared text had 80 exclamation points in it and he surely added more on his own as he went along.

“My predecessor and some of you here seek to bury the truth about Jan. 6th!” he declared about the 2021 attack on the Capitol instigated by Mr. Trump.

“We stopped you 50 times before and we will stop you again!” he vowed about Republican efforts to repeal the Affordable Care Act.

“My God, what freedom else would you take away?” he demanded after condemning the overturning of Roe v. Wade by Trump-appointed justices.

If the subtext of the 68-minute speech was to calm Democrats and independents worried that he is too old to seek another term, Mr. Biden addressed the matter explicitly at the very end, referring to “other people my age,” meaning Mr. Trump, who is 77 and also has moments of public confusion and memory lapses.

“My fellow Americans, the issue facing our nation isn’t how old we are, it’s how old are our ideas,” Mr. Biden said. “Hate, anger, revenge, retribution are the oldest of ideas. But you can’t lead America with ancient ideas that only take us back. To lead America, the land of possibilities, you need a vision for the future and what can and should be done.”

The president’s address seemed to get under Mr. Trump’s skin. “That may be the Angriest, Least Compassionate, and Worst State of the Union Speech ever made,” Mr. Trump wrote on his social media site afterward, including his own exclamation point. “It was an Embarrassment to our Country!”

For many watching, the speech surely generated a different impression of Mr. Biden than he sometimes leaves in public appearances, when he can appear frail and halting. While he mangled his lines at points and interrupted his speech to cough a couple times, he came across as far more commanding and energized than some of his supporters had feared.

More than most presidents on such occasions, he departed from the prepared text on the teleprompter to ad-lib lines — at times curiously, as when he started talking about Snickers bars “with 10 percent fewer Snickers in them,” at other times in response to the rowdiest members of the audience in front of him.

At one point, Mr. Biden had almost a repeat of last year’s State of the Union address, when he turned the tables on protesting Republicans over Social Security. “Republicans can cut Social Security and give more tax breaks to the wealthy,” he said, at which point G.O.P. lawmakers interrupted with boos and catcalls.

“You guys don’t want another $2 trillion tax cut?” he said with a smile on his face. “I kind of thought that’s what your plan was. Well, that’s good to hear.”

At another point, when he invoked the bipartisan border deal rejected by Republicans, Representative Marjorie Taylor Greene shouted about the case of Laken Riley, a 22-year-old nursing college student from Georgia who was killed last month, according to authorities, by a Venezuelan migrant who had entered the country illegally. “Say her name!” she screamed.

Ms. Greene, the proudly rabble-rousing Republican from Georgia who used to espouse QAnon conspiracy theories, showed up wearing a red Make America Great Again hat and a “Say Her Name” T-shirt. Mr. Biden called her bluff and interrupted his speech to hold up a “Say Her Name” button that had been given to him. He went ahead to say Ms. Riley’s name — although he botched it by calling her “Lincoln” instead of “Laken.”

He added that “my heart goes out” to her family but asked “how many thousands” had been killed by people living in the United States legally and argued that passing the border bill would reduce illegal crossings. “Get this bill done,” he told Republicans. “We need to act now.”

Mr. Biden, who began attending State of the Union addresses in the early 1970s as a young senator, was clearly comfortable and enjoying the return to Capitol Hill. He took his time entering the chamber, shaking hands and chatting with lawmakers, even making a playful face at Ms. Greene when he saw her hat. Likewise, he hung around long after the speech, rehashing its best moments with Democrats who surrounded him on the floor.

Unleashed and unyielding, Mr. Biden seemed to relish the showdown. While he boasted of his accomplishments and rattled off the usual litany of policy pronouncements as presidents usually do, he made no aspiration to lofty rhetorical flourishes.

He mentioned only in passing his “unity agenda” in a speech with almost no unity in it. Instead, he conveyed the impression of a candidate itching for a fight, coming across as more combative than even the bellicose Mr. Trump did in the same setting.

“We will not walk away,” Mr. Biden said early in his address. “We will not bow down. I will not bow down.”

He was speaking of Russia at that moment. But he seemed to also mean himself.

Steve Nikoui, the father of a U.S. Marine who was killed in 2021 during the evacuation of U.S. troops from Afghanistan, was arrested and charged with a misdemeanor for interrupting President Biden during his State of the Union address, according to Capitol Police.

Mr. Nikoui yelled “Abbey Gate, Abbey Gate” during the president’s speech, a reference to the place where his son, Lance Cpl. Kareem Nikoui, and 12 other troops were killed during the chaotic final days of the U.S. presence in Kabul, Afghanistan.

Police officers quickly removed Mr. Nikoui, 51, from the gallery where he was a guest of Representative Brian Mast, Republican of Florida. Mr. Biden paused briefly during the interruption but moved on quickly.

A statement from the Capitol Police said officers had warned Mr. Nikoui to stop, and when he did not, they removed him from the chamber.

In the statement, officers said: “This is a routine charge on Capitol Hill. People who illegally demonstrate/disrupt Congress typically are released after they pay a $50 fine, so the misdemeanor charge is resolved without going to court.”

Mr. Nikoui has been a vocal critic of Mr. Biden since the death of his son. In August 2021, he told The Daily Beast that he blamed the president for the tragedy.

“They sent my son over there as a paper pusher and then had the Taliban outside providing security,” Mr. Nikoui said at the time, according to the news organization.

“I blame my own military leaders,” he said, adding, “Biden turned his back on him. That’s it.”

President Biden used his State of the Union address on Thursday to launch a series of fiery attacks against former President Donald Trump, a competitor whom he did not mention by name but made clear was a dire threat to American democracy and stability in the world.

In a televised speech to a joint session of Congress, Mr. Biden brought the energy his allies and aides had hoped he would display to warn of what could happen should Ukraine continue to lose ground to Russia. Invoking an overseas war at the top of his address was an unusual introduction to a speech that was in many ways a political argument for his re-election.

“Not since President Lincoln and the Civil War have freedom and democracy been under assault at home as they are today,” Mr. Biden said, raising his voice to a shout. “What makes our moment rare is the freedom of democracy, under attack both at home and overseas.”

Mr. Biden’s speech had to accomplish several goals at once, including taking credit for an economy that has outperformed expectations but whose effects many Americans say they cannot feel. In a speech that ran for an over hour, he ran through a lengthy list of issues, including immigration, abortion, prescription drug costs and the war in Gaza.

He also engaged in a back-and-forth with congressional Republicans, picking up a button circulated by Republicans that called for people to say the name of Laken Riley, a Georgia nursing student who was killed in February.

The authorities have charged a Venezuelan migrant, who crossed into the United States illegally and was then released on parole, in the case.

Mr. Biden said Ms. Riley’s name, then added: “To her parents, I say, my heart goes out to you. Having lost children myself, I understand,” he said at one point, going off script and addressing Republicans by describing the accused as “an illegal.” The comment drew criticism from immigrant advocates and members of his own party who see the term as dehumanizing.

He also said there were thousands of murders committed by “legals.”

Mr. Biden used his time in front of one of the biggest audiences he will have before the November election to tell Americans that personal freedoms, diplomatic relationships and democratic rule in the United States are at stake if Mr. Trump is re-elected.

Mr. Biden assailed Mr. Trump for his soft treatment of President Vladimir V. Putin of Russia, whose troops invaded Ukraine more than two years ago. “If anybody in this room thinks Putin will stop in Ukraine, I assure you he will not,” Mr. Biden said, warning that the world was watching the United States.

“We will not bow down,” Mr. Biden said. “I will not bow down.”

He called out the former president’s behavior, including Mr. Trump’s lie that Mr. Biden had stolen the 2020 election from him.

“You can’t love your country only when you win,” Mr. Biden said.

Mr. Trump, never one to sit quietly, responded to many of Mr. Biden’s points in a stream of real-time posts on his social media site, Truth Social. “Putin only invaded Ukraine, because he has no respect for Biden,” he asserted in one post.

Ahead of the speech, Mr. Biden was under pressure to address the issue of his age. He laced his argument with humor — “I know I may not look like it, but I’ve been around a while,” he said, adding that his 81 years had taught him to “embrace freedom and democracy” and “to give hate no safe harbor.”

“Now some other people my age see a different story: an American story of resentment, revenge and retribution. That’s not me,” Mr. Biden said, a clear jab at his predecessor, who is four years younger and whose victory speech after Super Tuesday primary elections portended a dark future for America, a country he referred to as “third world.”

Mr. Biden also tried to quell dissatisfaction within his own party over his handling of the conflict in Gaza. Earlier on Thursday, the Biden administration said the United States would build a temporary seaport off Gaza to assist with the delivery of humanitarian aid.

“Israel also has a fundamental responsibility, though, to protect innocent civilians in Gaza,” Mr. Biden said.

The Israel-Hamas war has become a serious vulnerability for Mr. Biden. United Nations officials warn that famine is imminent in Gaza, and progressive voters of the Democratic Party are deeply angry with Mr. Biden’s support for Israel.

“To the leadership of Israel, I say this: Humanitarian assistance cannot be a secondary consideration or a bargaining chip,” he said. “Protecting and saving innocent lives has to be a priority.”

Of the hostages still held by Hamas, Mr. Biden said that his administration “will not rest until we bring every one of your loved ones home.”

Mr. Biden said, as he has before, that the Israeli-Palestinian conflict would not end without a two-state solution.

During his address, Mr. Biden focused extensively on reproductive rights, which have become a galvanizing issue for his party. Republicans cheered the Supreme Court’s decision in 2022 to overturn Roe v. Wade, which had established a constitutional right to abortion, but the party has been hurt in state elections since. Several women invited by the White House or Democratic lawmakers on Thursday evening had suffered life-threatening medical complications during pregnancy.

“Clearly those bragging about overturning Roe v. Wade have no clue about the power of women,” Mr. Biden said. “But they found out when reproductive freedom was on the ballot and we won in 2022, 2023, and we’ll win again in 2024.”

Mr. Biden, who once told supporters that he was “not big on abortion” because of his Catholic faith, promised to restore Roe’s protections — something that will be difficult to do without a sizable majority in Congress.

Mr. Biden had prepared for pushback from Republicans, who jeered him at different points during last year’s address, calling him a “liar” and breaking into mocking laughter. On Thursday, Mr. Biden ribbed Republicans at several points, including when he said that they had enjoyed taking credit for federal investments that they had voted against. At one point, a lawmaker yelled, “Lies,” as Mr. Biden spoke.

The speech was a high-stakes appearance for Mr. Biden, who is trailing behind Mr. Trump by five percentage points, according to a recent New York Times/Siena College poll.

Both men are unpopular, but Mr. Trump holds enormous influence over a far-right faction of House Republicans who defied members of their own party in rejecting a bill that would restrict immigration into the United States, saying it was not strict enough. Mr. Biden is under pressure to find a solution with a Republican Party that has so far signaled it will avoid giving him a political victory before November.

The share of Americans who view immigration as the biggest problem faced by the United States has risen in recent months, and a surge of undocumented immigrants has put the Biden administration on the defensive as the campaign gets underway.

And though inflation has come down and the job market has outperformed expectations, the data has done little to overcome a pervasive belief among many Americans that they simply are not better off than they were before. The Biden administration announced a plan on Thursday to lower housing costs for working families, and he explained how his economic policies had benefited families.

“It doesn’t make the news, but in thousands of cities and towns the American people are writing the greatest comeback story never told,” Mr. Biden said.

Within his economic message were hints about what Mr. Biden would do with a second term, including an effort to increase corporate taxes to at least 21 percent so, he said, “every big corporation finally begins to pay their fair share.” Such an initiative would be unlikely to succeed unless Democrats manage to hold the Senate and take back the House.

Republicans chose Senator Katie Britt of Alabama, who is nearly 40 years younger than the president, to deliver their response to Mr. Biden’s address.

“Our commander in chief is not in command,” Ms. Britt said. “The free world deserves better than a dithering and diminished leader.”

The 20 guests who joined Jill Biden, the first lady, to watch the address were all invited to draw sharp distinctions with Republicans on issues like reproductive rights, prescription drug prices and furthering Western diplomacy.

Mr. Johnson had his own guest list, highlighting people connected to issues that Republicans believe are vulnerabilities for Democrats, including crime, the opioid epidemic and immigration. He also invited Ella Milman and Mikhail Gershkovich, the parents of Evan Gershkovich, a reporter for The Wall Street Journal who has been imprisoned in Russia since last March.

Last weekend at Camp David, the president practiced for several days for his speech. On Thursday night, after days of media speculation on how he would seem during this speech, he took his time as he entered the chamber, stopping to take selfies with supporters.

At different points in his address, Mr. Biden appeared relaxed, to the point that he ad-libbed about Snickers bars and potato chip bags, and engaged in a back-and-forth with Republicans over tax breaks. After the speech, when the chamber was mostly cleared out, Mr. Biden was still there, shaking hands with some House members and holding forth on Ukraine.

Senator Katie Britt’s team hopes viewers see her response to President Biden’s State of the Union as Reaganesque — but also, very maternal.

Before President Biden even arrived at the Capitol on Thursday night, a close ally of the Alabama Republican sent a document of talking points to conservative influencers suggesting words of praise they could offer after Ms. Britt’s speech.

“She came off like America’s mom — she gets it,” the document helpfully suggests. “She’s one of us. That’ll be families’ takeaway watching this.”

But Ms. Britt also came across like Ronald Reagan, it declared. “The conclusion of her border section was a real ‘Mr. Gorbachev, tear down this wall,’ moment,” another talking point said, referring to Reagan’s historic speech in Berlin.

Ms. Britt, who at 42 is the youngest Republican woman ever elected to the Senate, is on Donald J. Trump’s short list of potential running mates, according two people with direct knowledge of the list.

The talking points compared her State of the Union response to some of the most famous oratory in American history, calling it “reminiscent of Reagan’s message of that Shining City on a Hill.”

Comparing Ms. Britt to Mr. Biden, the document suggested saying that “it wasn’t just the massive age gap/contrast between the two” but that Ms. Britt “exposed a relatability gap — a truly generational schism.”

Mr. Biden is 81. Mr. Trump is 77.

A spokesman for Ms. Britt did not immediately respond to a request for comment.

“His speech was tone deaf,” the talking points declared, before either Mr. Biden or Ms. Britt had uttered a word. “Hers was the perfect pitch.”

Among the hundreds of guests who will fill the House chamber on Thursday evening — each invited to telegraph distinct political messages — will be dozens of reproductive rights advocates and providers invited by Democrats who are looking to put access to abortion and fertility treatments front and center this election year.

Twenty-eight Democrats in the House and at least seven in the Senate chose their guests for their reproductive health experiences or advocacy background. They include the first person born in the United States via in vitro fertilization, women who relied on I.V.F. to get pregnant, abortion providers and women who were denied abortions by state bans after learning of fatal fetal anomalies or developing conditions that threatened their health and fertility.

It is all part of an effort by Democrats to highlight their support for reproductive rights, while seizing on the stringent restrictions imposed by Republican-led states since the Supreme Court overturned Roe v. Wade. It is also a way for them to spotlight how Republicans — many of whom have backed abortion bans and the notion of fetal personhood — have endorsed policies that could put access to abortion and fertility treatments at risk.

“It’s the fight of our lives. We have Republicans — they want to either force women to stay pregnant, or prevent women from getting pregnant,” said Representative Lois Frankel of Florida, who invited Dr. Cherise Felix, an OB-GYN who fled Tennessee’s abortion ban to practice at a Planned Parenthood in West Palm Beach. “The threat of Donald Trump is real. It’s because of him that Roe v. Wade has been overturned, and we know that Joe Biden will be a warrior for us.”

After the Alabama Supreme Court ruled last month that frozen embryos should be considered children, a decision that imperiled access to I.V.F. in the state, Senator Tim Kaine, Democrat of Virginia, invited Elizabeth Carr — the first American conceived in a lab. Ms. Carr was born in 1981 in Norfolk, Virginia. (Alabama lawmakers passed a law on Wednesday to protect I.V.F. providers from criminal and civil liability.)

“It’s more important than ever that we commit to protecting access to I.V.F. services nationwide,” Mr. Kaine said in a statement.

Representative Katherine Clark of Massachusetts, the No. 2 House Democrat, invited Amanda Zurawski, a plaintiff in a lawsuit challenging Texas’ abortion ban who was permitted to undergo the procedure only after going into septic shock when her water broke at 18 weeks of pregnancy. On Thursday, Ms. Zurawski said that she has turned to I.V.F. to start a family after the infection she sustained in her earlier pregnancy compromised her fertility, and she moved her frozen embryos out of state after the Alabama ruling, fearing a similar restriction could come down in Texas.

Senator Patty Murray, Democrat of Washington, invited Kayla Smith, who spent thousands of dollars traveling there for an abortion in 2022 after being denied one in Idaho after she found out that her baby — which she emphasized on Thursday was “very wanted” — had fatal anomalies. Ms. Smith is a plaintiff in a lawsuit filed in September challenging Idaho’s abortion ban.

Ms. Murray said it was paramount that Democrats “shine a light on the horrific consequences of Republican abortion bans that have ripped away a woman’s right to make her own health care decisions.”

Democrats in Congress have introduced legislation to codify federal abortion rights and to protect access to I.V.F., but have faced Republican opposition. Last week, Senator Cindy Hyde-Smith, Republican of Mississippi, blocked quick passage of a bill to protect access to fertility treatments.

“It’s really clear who’s standing up for women and trust women to make decisions about their own bodies and about their own health care — it’s Democrats,” said Senator Tammy Duckworth, Democrat of Illinois, who invited Dr. Amanda Adeleye, a reproductive endocrinologist. “So my reminder to voters is remember who’s watching out for your reproductive rights. It’s certainly not Republicans.”