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

There were 10 arrests made during Monday's fencing breach at the DNC, Chicago Police Superintendent Larry Snelling told reporters on Tuesday.

"I couldn't be more proud of how Chicago Police Department responded under those circumstances," Snelling said. "We put on display the trainings and the preparation that we've been engaged in for over a year now. That being said, moving forward, we do expect to see, or protest or demonstrate tactics again. We're up to the challenge."

Snelling said there were 13 arrests total on Monday, which ranged from criminal trespass to battery on a police officer.

On reports that protesters were "assaulted" by police, the superintendent pushed back hard.

"Those police officers responded perfectly, and we got body cam footage to prove it. They were not hospitalized for injuries."

-ABC News' Luke Barr

For the first half of 2024, a huge question for the Biden campaign was whether he would lose a critical amount of support with key blocs of voters that supported him in 2020, such as Black voters and young voters. Now, however, Harris is running instead, and her coalition isn’t necessarily the same as Biden’s.

In a new article, 538 Senior Researcher Mary Radcliffe took a deep dive into national polls to answer the question of who, exactly, makes up the Harris coalition. She also compared Harris’ polling numbers among various racial, gender and age groups to Biden’s. It turns out that Harris has shored up a lot of Biden’s weaknesses -- and it’s pretty surprising which group she is outpacing him with by the most.

—538’s Nathaniel Rakich

On Tuesday night, former President Barack Obama gives a highly anticipated speech in which he is expected to make a forceful case for electing Harris. It won’t be the first time that Obama spoke glowingly of Harris -- in fact, he has gotten in trouble for it before. Back in 2013, he spoke at a fundraiser in California that Harris attended and said of the then-California attorney general, “She is brilliant and she is dedicated and she is tough, and she is exactly what you'd want in anybody who is administering the law, and making sure that everybody is getting a fair shake. She also happens to be by far the best-looking attorney general in the country.” The comment on Harris’s looks sparked a backlash for being sexist and inappropriate, and he apologized the next day.

—538’s Nathaniel Rakich

When former President Barack Obama and former first lady Michelle Obama speak at the DNC on Tuesday, they will highlight their friendship with Harris that they say goes back 20 years, according to a source familiar.

The Obamas have been in regular touch with Harris over the years, providing counsel and being a sounding board, too, the source said. Over the last few months in particular, the Obamas have been in close contact with the vice president and supported her campaign in any way they are able, the source said.

Their remarks on Tuesday will turn the page from the Biden administration and focus on how Harris and Walz are the leaders the country needs right out, the source said.

The source highlighted how the Obamas have campaigned for Harris and worked to energize young voters.

-ABC News' MaryAlice Parks