DNC 2024 Day 2: 'Yes, she can': Obama endorses Harris, blasts Trump

At Harris' rally in Milwaukee, the campaign announced in the arena that the vice president will be broadcast into the DNC and that they want the crowd here to "bring the energy."

"I'm really going to need this energy when they broadcast this live, right?" said Jaliah Jefferson, Wisconsin deputy organizing director, Milwaukee. "VP Harris will be beamed into TVs all across the country."

"So when it's our moment, we need to get loud and leave no doubt that Wisconsin is going to send Kamala Harris and Tim Walz to the White House," she added.

Crowds have been waiting for hours to enter the Fiserv Forum -- where the RNC was held last month. The arena is packed with people and it's a party vibe. The music has been pumping loudly, people are dancing and waving their light-up wristbands. The bass in the music is so loud the floor is vibrating.

The roll call for the DNC has begun.

State delegates will go in alphabetical order, with a DJ playing music related to each state.

Pennsylvania Gov. Josh Shapiro told ABC News Live Prime anchor Linsey Davis in an interview from the DNC that he is seeing "incredible enthusiasm" for the Harris-Walz campaign on the ground.

Pennsylvania Gov. Josh Shapiro told ABC News Live Prime anchor Linsey Davis in an interview from the DNC that he is seeing "incredible enthusiasm" for the Harris-Walz campaign on the ground.

"Kamala Harris is showing up in communities that are oftentimes ignored and left behind," Shapiro said, adding that she's sending a message to Pennsylvanians that she cares about them.

"I think as this race progresses, you're going to continue to see real momentum on her part," he said.

Spotted at the United Center snapping selfies was Michael Cohen, Trump's former attorney who was a star witness in his New York hush money trial.

The Trump campaign, meanwhile, continued to hold its daily press conference this morning just three miles away from the DNC site to "remind folks what Donald Trump is running for."

At the press conference, which focused on the issue of crime, Rep. Byron Donalds sought to counter Harris' prosecutor persona by painting her as soft on crime and pointing to some of her previous statements -- including her previous call to "redirect resources" from police.

Donalds also pushed a familiar line of attack against the Harris campaign -- that they are lacking in enough policy positions and instead are focusing on "joy and vibes."

ABC News asked the Florida Republican what type of messaging he is looking to see from Trump on the campaign trail this week amid tightening polls.

"I think this election is really a choice election, it's a contrast election, even more so than some others. We have very stark differences with Kamala," Donalds said, while pointing to the subjects of immigration, crime and foreign policy.