After proclaiming, "America, we are not going back," the crowd erupted into chants of "we're not going back."

The chants got so loud that at first, you couldn't hear Harris over the speakers.

Harris called the election "one of the most important in the life of our nation" as she pivoted to talking about Trump.

She called him an "unserious man" who if put back in the White House would have "extremely serious" consequences.

"Consider not only the chaos and calamity when he was in office, but also the gravity of what has happened since he lost the last election," she said, going on to discuss the insurrection and fraud conviction.

"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. "You can always trust me to put country above party and self, to hold sacred America's fundamental principles, from the rule of law to free and fair elections, to the peaceful transfer of power. "

"I will be a president who unites us around our highest aspirations, a president who lead us and listens, who is realistic, practical and has common sense and always fights for the American people from the courthouse to the White House," she continued. "That has been my life's work."

I wrote about this earlier today in our 538 politics chat, but the Harris campaign has been working to reframe their party's position on the economy, an issue that's always at the top of voters' minds. It's an issue that Democrats have been lagging behind Trump on throughout this election cycle, though Harris has been gaining a bit of ground since she entered the race.

Other DNC speakers have touted Harris's history of working at McDonald's and her middle-class roots, while her speech emphasized that again tonight with her stories of growing up in Oakland. I expect more of this on the campaign, as Walz, a former teacher, and Harris try to connect with working-class voters.

—538's Monica Potts