At her first campaign speech since replacing President Joe Biden as the Democratic nominee for president, Vice President Kamala Harris attacked Donald Trump on Tuesday.  

Speaking to a crowd at West Allis Central High School in a Milwaukee suburb in Wisconsin – a battleground state in the November 5 election – Harris said, "In this campaign, I promise you I will proudly put my record against his any day of the week."

"Do we want to live in a country of freedom, compassion and rule of law, or a country of chaos, fear and hate?" she asked the crowd. 

This comes as a nationwide Reuters/Ipsos poll conducted on Monday and Tuesday after Biden withdrew from the race showed Harris leading Trump 44% to 42% among registered voters.

The polls, a week ago, before Biden withdrew, showed Harris and Trump tied at 44%.

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Using her background as a prosecutor and the attorney general of California, where she dealt with a variety of criminals and con artists, Harris claimed to know Donald Trump's personality.

"Before I was elected United States Senator, I was elected Attorney General of the State of California, and I was a courtroom prosecutor before then, and in those roles, 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, so hear me when I say I know Donald Trump's type," Harris stated. 

She said that she has enough delegates' backing to win the Democratic nominee.

"I am told as of this morning that we have earned the support of enough delegates to secure the Democratic nomination," Harris revealed. In order to prepare the Democratic Party for success in November, Harris continued, she would spend the upcoming weeks bringing everyone together.

However, delegates remain free to vote for any candidate at the August Democratic National Convention (DNC) or during a potential virtual Democrat roll call before the event in Chicago.

Just hours before the delegate vote, Democratic fundraiser ActBlue disclosed that Harris had raised $81 million in the first 24 hours of her campaign, setting a record for the largest single-day fundraising total by a presidential candidate in history.

Meanwhile, Donald Trump, the former US President who is vying to win the presidency again, promised on Tuesday to participate in at least one presidential debate with Harris.

"Oh, yes, absolutely. I want to. I think it's important," he said on a call with reporters, adding, "I would be willing to do more than one debate, actually."

On Monday, Trump declared that Harris would be "easier" to defeat than Biden in November's election.

"She's far more radical than he is... So I think she should be easier than Biden, because he was slightly more mainstream, but not much," Trump said on a call with reporters.

Meanwhile, Barack Obama, former Democrat US president, expressed his trust in the Democratic Party's ability to set up a process to select the best candidate for president on Sunday, declining to endorse Harris.

The same day, NBC News revealed that rather than nominating Harris right away, Democrats in the US Congress stated they would like to have an open election to select the Democratic nominee to succeed Biden.

Meanwhile, in a statement, former US President Bill Clinton and his spouse Hillary said that they were "honored to join the President in endorsing Vice President Harris."