Kamala Harris held her first rally as a presidential candidate after securing enough Democratic delegates to clear a path to the nomination.
The Vice President spoke in Milwaukee in the critical battleground state of Wisconsin, where the Republican National Convention was held last week.
As she took to the stage she was met by roars of approval from the crowd and shouts of “Kamala, Kamala!”.
During her address she said she will “proudly put” her record against that of her rival in the presidential race, Donald Trump.
Ms Harris praised Joe Biden and claimed Donald Trump was trying to “take our country backward”, saying: “Do we want to live in a country of freedom, compassion and rule of law, or a country of chaos, fear and hate?”
She also joined in a “we are not going back!” chant from the crowd and said she will ensure every worker should have freedom to join a union.
Ms Harris also emphasised her commitment to reproductive rights, an issue that has plagued Republicans since the US Supreme Court – powered by three Trump-appointed justices – eliminated a nationwide right to abortion in 2022.
On Monday night during a visit to campaign headquarters in Delaware, Harris, 59, offered a taste of how she plans to attack her rival, drawing on her experience as a prosecutor pursuing “predators” and “fraudsters”.
“I took on perpetrators of all kinds. Predators who abused women, fraudsters who ripped off consumers, cheaters who broke the rules for their own gain,” she told supporters. “So hear me when I say I know Donald Trump’s type.”
Harris has now raised more than $100m from 1.1 million different donors — 62 per cent of them first-time contributors — between Sunday and Monday, a campaign official said.
She has also secured the endorsement of Hollywood actor and major Democrat donor George Clooney, who hailed her “historic” White House bid.
Clooney called earlier this month for Biden to step down as the Democrat candidate, saying he “was not the Joe ‘big f**king deal’ Biden of 2010. He wasn’t even the Joe Biden of 2020”.
He told CNN on Tuesday: “President Biden has shown what true leadership is. He’s saving democracy once again. We’re all so excited to do whatever we can to support Vice President Harris in her historic quest.”
Harris also secured the endorsement of Senate majority leader Chuck Schumer and House minority leader Hakeem Jeffries yesterday, having won the support of Democrat grandee Nancy Pelosi on Monday.
“The vast majority of my senators quickly and enthusiastically endorsed her, so now that the process has played out, from the grassroots bottom-up, we are here today to throw our support behind Vice President Kamala Harris,” Schumer said.
Jeffries said: “Vice President Harris has earned the nomination from the grass roots up and not the top down.
“I’m proud to strongly endorse Kamala Harris to be the 47th president of the United States of America.”