CHICAGO — Vice President Kamala Harris accepted the Democratic presidential nomination Thursday, using the most consequential speech of her political career to cast herself as an avatar of America’s middle class and an avenue to usher the country away from the abrasive style of politics embraced by Republican nominee Donald Trump.

“Our nation with this election has a precious, fleeting opportunity to move past the bitterness, cynicism, and divisive battles of the past,” she said in a speech that reflected on her unexpected journey to the top of her party and to the cusp of becoming the nation’s first female president. “A chance to chart a new way forward. Not as members of any one party or faction, but as Americans.”

Harris delivered a withering critique of Trump while also making several appeals to bipartisanship and patriotism during her speech, combating efforts by Trump and his allies to brand her as radical or somehow foreign. As she spoke, a packed, jubilant crowd of supporters clapped and waved American flags. Many were wearing white, the color associated with the suffragist movement. More than 100,000 red, white and blue balloons dropped at the end of her speech.

The celebratory moment marked how quickly Democrats’ fortunes have changed over the past two months, in which the party agonized over a disastrous debate performance by President Joe Biden, endured weeks of public infighting over his candidacy and then swiftly united behind Harris after Biden dropped out on July 21. The fast-moving turn of events has injected a fresh wave of energy and enthusiasm into the Democratic Party but has also left some voters with a sense of uncertainty about Harris.

Harris began her speech with a shout-out to second gentleman Doug Emhoff, noting it was their wedding anniversary, and praise for Biden’s “inspiring” character before launching into stories about her childhood and background. But it did not take long before she launched into an extended attack on Trump, blasting him over his legal judgments, protectionist economic policies, his criticism of allies and his praise of dictators.

She also made her most extended remarks yet on the war in Gaza, addressing an issue that has been at the heart of a lengthy conflict within the party.

“Let me be clear: I will always stand up for Israel’s right to defend itself and I will always ensure Israel has the ability to defend itself,” she said, before adding that “what has happened in Gaza over the past 10 months is devastating.”

She reiterated her call for a cease-fire and a release of hostages in Gaza. “President Biden and I are working to end this war such that Israel is secure, the hostages are released, the suffering in Gaza ends, and the Palestinian people can realize their right to dignity, security, freedom and self-determination,” she said.

As she made a case for her unconventional candidacy, she sought to put it against the backdrop of her life story, describing an only-in-America tale that took her from a working-class neighborhood in Oakland to the becoming the first woman of color to lead a major party ticket for the presidency.

Calling herself “no stranger to unlikely journeys,” Harris recounted the story of being raised by an immigrant mother from India who saved up for a decade before she could buy a home.

Citing her work as a prosecutor who began cases with the five words “Kamala Harris, for the people,” she pledged to represent a diverse country full of people chasing dreams of their own.

“On behalf of everyone whose story could only be written in the greatest nation on earth, I accept your nomination to be president of the United States of America,” she said.

The convention also featured additional members of Harris’s family, as part of an effort to show the softer sides of the vice president. Harris’s sister, niece, stepdaughter and goddaughter praised her for being a steady and inspiring figure in their lives. Her great nieces joined actress Kerry Washington onstage to teach the crowd how to pronounce Harris’s first name, breaking it down into two parts: “comma” and “la.” They then led the arena in practicing the proper pronunciation — a dig at Trump who routinely mispronounces her name.

“Confusion is understandable. Disrespect is not,” Washington said. “Tonight, we’re going to help everybody get it right.”

Harris took the stage to more than two minutes of raucous, sustained applause and chants, a welcome even more exuberant than the adulation that has greeted a series of Democratic Party stars and celebrities at the United Center this week.

Democrats in the arena were especially excited on Thursday, giving the scene the feeling of a rock concert. In between speakers, a DJ appeared on the main stage, encouraging attendees to stand up and dance — featuring a medley of pop hits including “Shake it Off” by Taylor Swift and “Celebration” by Kool & The Gang.

While speaking to the party faithful in the room, Harris also sought to offer a broader appeal to the moderate voters she will need to win over to prevail in battleground states.

“I know there are people of various political views watching tonight. And I want you to know: I promise to be a president for all Americans,” she said, presenting herself as a bridge builder willing to unify a country riven by political strife and infighting. “You can always trust me to put country above party and self. … I will be a president who unites us around our highest aspirations. A president who leads — and listens. Who is realistic, practical and has common sense.”

Aides said Harris’s goal was to offer biographical details about her life and background while connecting her story to the modern-day struggles and strivings of Americans.

“We know that the American people don’t know that much about the vice president,” Jen O’Malley Dillon, Harris’s campaign chair, said in an interview with The Washington Post on Thursday. “So we really have an opportunity to fill that in for them and to fill that in in a way that really shows how she’s going to make a difference in their lives.”

Harris and her aides spent several days in her Chicago hotel preparing for the speech, aiming to deliver a crisper performance than the meandering 92-minute acceptance speech Trump delivered last month when accepting the Republican nomination in Milwaukee.

She leaned in on a theme embraced by several speakers over the course of the convention — aiming to belittle Trump rather than cast him as a larger-than-life threat to the nation. Former presidents Barack Obama and Bill Clinton were among several party leaders who used their speeches to mock Trump as a self-centered politician who is mostly concerned about his own well-being.

“In many ways, Donald Trump is an unserious man,” she said. “But the consequences of putting Donald Trump back in the White House are extremely serious.”

Trump responded in real time to Harris, using his Truth Social platform to offer his thoughts on her acceptance speech.

“Kamala’s biography won’t lower prices at the Grocery Store, or at the Pump!” he wrote, focusing on inflation as she talked about her background.

Trump also repeatedly pointed to the fact Harris is already in office. “ALL TALK, NO ACTION — Why didn’t she do it three and a half years ago?” he wrote.

Harris slammed Trump over his legal judgments, economic policies and his role in appointing Supreme Court justices who overturned Roe v. Wade’s right to an abortion. She said a second Trump term would be more dangerous after another Supreme Court ruling, which found that presidents had immunity from certain prosecutions.

“Just imagine Donald Trump with no guardrails and how he would use the immense powers of the presidency of the United States,” Harris said. “Not to improve your life. Not to strengthen our national security, but to serve the only client he has ever had: himself.”

In laying out the contours of her journey to the nomination, Harris highlighted parts of her biography that dovetail with the themes of her campaigns, including her career as a prosecutor who took on fraudsters, transnational gangs and sexual predators.

During her campaign for president, Harris has repeatedly cited her prosecutorial background, asserting that she is well positioned to go toe-to-toe with Trump, who was convicted in Manhattan earlier this year of 34 felony counts of falsifying business records to conceal a hush money payment to an adult-film actress.

“I know Donald Trump’s type,” Harris frequently says at her campaign events.

Harris also used her speech to lean into the idea of patriotism, calling out Trump for often disparaging the country and for inspiring the Jan. 6, 2021, attack on the U.S. Capitol.

The convention organizers continued to lean into patriotism on Thursday night, passing out American flags to delegates and “USA” signs as Democrats seek to reclaim the message and imagery from the Republican Party and Trump, who has literally tried embracing the American flag.

When Rep. Ruben Gallego (D-Ariz.), a who served as a U.S. Marine, spoke, he was joined onstage by more than two dozen other federal, state and local lawmakers who also served in the military.

“Politicians like Donald Trump don’t stand with us,” Gallego said.

Another veteran, former congressman Adam Kinzinger (R-Ill.), who broke with Trump over his attempts to overturn the 2020 election, gave Democrats a boost in their effort to challenge Republicans on patriotism.

“I want to let my fellow Republicans in on a secret: The Democrats are as patriotic as us,” he said. “They love this country as much as we do.”

The crowd broke out into chants of “U-S-A!”

Harris has oriented much of her campaign around the idea of “freedom” — often coming onstage to the soundtrack of Beyoncé’s 2016 hit “Freedom” — and has used the term to refer to reproductive rights, voting rights, civil rights and economic opportunity.

Harris’s detractors say she has spoken largely in platitudes and failed to outline a specific policy agenda or answer questions about how she would use the powers of the presidency if elected. Republicans have sought to fill in the gaps by casting her as a radical liberal, pointing to her California background and to some of the policies she backed during a short-lived run for the presidency in 2019.

“She became the Nominee without receiving one Vote, stealing the Nomination from Crooked Joe Biden who earned it by getting 14 Million Votes,” Trump wrote Thursday on Truth Social, promising to “expose all of her Radicalism, the horrible job she did at the Border, Crime, and Foreign Relations, and her Weaponization against her Political Opponent.”

Unlike five years ago, Harris has not had to face grueling primary contests, debates or town halls with voters forcing her to state where she stands on key matters of policy. Her campaign has disavowed some of her more liberal positions from 2019, saying she no longer supports a ban on fracking, a Medicare-for-all policy, mandatory gun buyback initiatives or removing penalties for those who cross the border illegally.

As both Democrats and Republicans offer competing versions of Harris to the country, her speech Thursday offered her an unfiltered opportunity to make her own case to the country for her candidacy. Before she spoke, several Democratic leaders offered their full-throated endorsements.

“You know what I love best about Kamala Harris? Kamala Harris can’t be bought,” said Sen. Elizabeth Warren (D-Mass.), in an apparent reference to the 1972 campaign slogan of Shirley Chisolm, the first woman to run for president. “And she can’t be bossed around.”

Speakers used their remarks Thursday to discuss themes of gun violence, military service, the environment and patriotism on the final night of the convention. During one particularly emotional moment, several Americans impacted by mass shootings gave testimonials about their harrowing experiences and the pain of their losses.

“We will organize, we will advocate, we will run for office,” said Rep. Lucy McBath (D-Ga.), who ran for Congress after her son was shot and killed. “And we will join with Americans from small towns and big cities to keep our communities safe.”

Harris’s comments on Gaza were notable. Ahead of Harris’s speech, thousands of protesters — led by young people, liberal voters and Arab Americans whose votes Democrats typically rely on in close races — complained about the Biden administration’s handling of the war and criticized party officials for not allowing a Palestinian to speak during the convention. The protests were less disruptive than many Democrats expected, in part because Harris’s ascension to the top of the party upended original plans to protest Biden over his support for Israel’s military campaign. Harris has expressed support for Israel’s right to defend itself but has spoken more forcefully about the plight of innocent Palestinians killed by Israeli bombs.

During the convention, party leaders have also faced questions over their treatment of “uncommitted” delegates who represent voters who withheld votes from Biden during the Democratic primaries because of his handling of the war in Gaza.

Negotiations were ongoing throughout the event over whether to allow a Palestinian American to address the convention from the stage — something that ultimately did not happen.

The discussions were fraught in part because Democrats have sought to project a sense of unity during their convention, realizing that millions of people would be tuning in and learning about Harris for the first time.

“The convention itself is an opportunity not just to speak to people in the hall but to speak to everyone in the country,” said O’Malley Dillon. “That’s been a big part of what we’re doing every day here.”

Isaac Arnsdorf, Hannah Knowles and Yasmeen Abutaleb contributed to this report.