US Vice-President Kamala Harris launched a vigorous offensive against Donald Trump in the first rally of her White House campaign, framing the upcoming November election as a choice between a former prosecutor and a convicted felon.

Addressing a crowd of about 3,000 in Wisconsin, a key battleground state, Harris compared her Republican opponent to the fraudsters she prosecuted during her career. Trump, in response, criticized her border policies and posted on social media, “Lyin’ Kamala Harris destroys everything she touches!”

This rally came a day after Harris secured the majority support from Democratic delegates, positioning her as the party’s nominee. On Sunday, President Joe Biden announced his withdrawal from the race, endorsing Harris amid growing pressure from top Democrats and donors following his poor performance in a late-June debate against Trump.

Harris’s nascent campaign quickly amassed over $100 million (£77 million) within 36 hours of Biden’s exit. Further boosting her momentum, a new national poll from Reuters and Ipsos showed her leading Trump by two points, 44% to 42%.

Taking the stage to applause at a high school in a Milwaukee suburb on Tuesday, Harris emphasized her tenure as California’s attorney general. “I took on perpetrators of all kinds,” she said. “Predators who abused women. Fraudsters who ripped off consumers. Cheaters who broke the rules for their own gain.”

“So hear me when I say I know Donald Trump’s type,” Harris continued. “In this campaign, I promise you, I will proudly put my record against his any day of the week.”

The crowd responded enthusiastically, chanting “Kamala! Kamala!” Observers noted this energy contrasted sharply with the atmosphere at Biden’s events earlier in the electoral cycle. When Trump’s name was mentioned, many in the audience chanted “lock him up,” mirroring the chants at Trump’s rallies against Hillary Clinton in 2016.