Vice President Kamala Harris spoke of her joy on Sunday during a raucous return home after being sworn in as the Democratic presidential nominee, surrounded by supporters she has known for decades, but also warned of a bleak future for the country if Democrats do not win the November election.

“It's good to be home,” Harris told a crowd of about 700, who cheered and rose to their feet as she took the stage at a San Francisco hotel ballroom. “This room is filled with dear friends and longtime supporters that I've known my whole career. … We've been through a lot together, and I want to thank all of you here for your love and your years of support and friendship and dedication to this country.”

The atmosphere at the fundraiser was warm and optimistic — one woman in the front row waved a sign that read “Make America Fun Again” — but Ms. Harris grew serious as she argued that fundamental rights such as health care, same-sex marriage and abortion were at stake in her fight with former President Trump.

“We know what we need to do: We need to go door to door, we need to register people to vote, we need to get people to the polls, and every day counts,” she said. “And that's why we will win, but we can't take anything for granted.”

The event brought together House Speaker Honorable Nancy Pelosi, Governor Gavin Newsom, San Francisco Mayor London Breed, Congresswoman Barbara Lee, San Francisco Giants CEO Larry Baer and numerous other elected officials and donors, raising more than $12 million in the city where Harris built her political career. Tickets ranged from $3,300 to $500,000.

Harris served as a prosecutor and city attorney in San Francisco before being elected district attorney in 2002, a position that paved the way for her later career as state attorney general and U.S. senator.

“This is a wonderful day to welcome Kamala Harris back to her home state of California,” Pelosi said as she introduced the vice president. “She makes us all so proud. She gives us so much joy and hope.”

The event felt like a family reunion. Harris' niece's young children posed for photos in front of a large Harris and Walz campaign sign on stage. She addressed several attendees from the stage, with Newsom drawing the most attention. She reminisced about the day she was sworn in as district attorney and he as mayor in San Francisco in 2004, and spoke of their work in support of same-sex marriage that year.

“I've known Gavin for many years as a friend and colleague,” she said. “In front of all of our friends here, I want to thank you for being an extraordinary leader for California and the country.”

The event capped a tumultuous three weeks of the presidential campaign, with President Biden announcing he would not seek reelection, Democrats quickly rallying around a running mate and Harris selecting Minnesota Governor Tim Walz as her running mate.

In his first interview since announcing he would not seek re-election, Biden said his decision was driven by the importance of beating Trump, concerns that some members of the House and Senate feared a Biden candidacy would hurt their own chances and that a Biden candidacy could be a “real distraction.”

“The issue that remains important to me is preserving our democracy. This is no joke,” Trump said in an interview that aired Sunday on CBS. “It's a great honor to be president, but I think I have an obligation to my country to do the most important thing I can do, which is defeat Trump.”

Harris and Walz toured battleground states last week with large crowds.

“People come to these events and they bring so much joy. They're singing and dancing in the aisles long before we even get there,” Harris said. “They're not just coming because we need to defeat Donald Trump, they're coming because they believe in our country and they believe in our freedom.”

On Saturday, Democrats rallied the support of the powerful Las Vegas union, the Culinary Workers Union, and announced that Harris supports a proposal to not tax tips, an idea that is hugely popular among service industry workers and that President Trump also supported in June.

“Copycat Kamala directly plagiarized President Trump's policy proposal to eliminate tip taxes, which would allow hardworking service workers to keep more of their hard-earned money,” the Republican campaign said in a statement.

Sunday's fundraiser came four years to the day since Biden selected Harris as his running mate and months after her failed 2020 presidential campaign.

“This is the best decision I've ever made,” Biden wrote in a fundraising appeal. “Kamala is smart. She's tough. She'll be a great president.”

The California Republican Party chose the venue for a Sunday fundraiser to question Democratic leadership and point out dysfunction in San Francisco.

“For anyone who doesn't know what a Harris presidency would be like, just take a look at her hometown, where crime is rampant, homelessness is on every street corner, storefronts and office space stand empty, businesses are closed and people are leaving with no intention of returning,” state Republican Party Chair Jessica Milan Patterson said in a statement.

California is a heavily Democratic state, so there will be no elections in November. But the state is home to a wealthy donor base that provides the most campaign cash to candidates in both parties. Republican vice presidential candidate Sen. J.D. Vance of Ohio recently headlined two fundraisers in the state. On Tuesday, Sen. Walz will attend a fundraiser in Newport Beach, the same day that Sen. Doug Emhoff, the second-term senator, will hold one in Los Angeles.

Attendee Suzi Tompkins Buell, co-founder of Esprit and The North Face, said she has known Harris since the 1990s and could not remember ever seeing such energy among Democrats. She attributed the energy to the “danger from within” posed by Harris' candidacy and the possibility of Trump being re-elected.

“Kamala's youthfulness and positive energy are like a cool breeze on a hot and humid day — so refreshing and hopeful,” said Tompkins Buell, who served as finance chair during Harris' time as district attorney and attorney general.

“She's been a big part of our community for years,” he added. “I'm so impressed with her consistency. She's so sure of herself and her style has always been the same, it's only getting better. It's all so impressive.”