2nd Democratic debate highlights: What you need to know

Night two of the first Democratic debates in the 2020 cycle made the preceding night look like the calm before the storm.

With more top-tier candidates onstage than on Wednesday, Thursday's debate delivered a feistier battle of ideas.

Lesser-known candidates took shots at those stationed at the middle podiums -- the places on stage reserved for the candidates with the highest polling averages -- but the starkest moment of direct criticism came from those leading the pack.

California Sen. Kamala Harris, the only African American candidate onstage, took former Vice President Joe Biden to task on issues of race, while also managing to avoid any attacks from other candidates.

In addition to Biden and Harris, candidates who took the stage Thursday night included former , Vermont Sen. Bernie Sanders, South Bend, Indiana Mayor Pete Buttigieg, Colorado Sen. Michael Bennet, New York Sen. Kirsten Gillibrand, former Colorado Gov. John Hickenlooper, California Rep. Eric Swalwell, spiritual author Marianne Williamson and entrepeneur Andrew Yang.

A poignant moment for Harris and a direct hit for Biden

The former prosecutor didn't slip up. Her delivery seemed smoothly rehearsed and sharply pointed.

Harris hit Biden with two points: As the only African American candidate on stage, she told Biden she did not believe he was racist but said his comments in recent weeks about senators who supported segregation were "hurtful." And then she attacked his votes against busing, a policy aimed at bringing students across school district lines to desegregate schools.

That issue, Harris said, was personal.

"There was a little girl in California who was part of the second class to integrate her public schools and she was bused to school every day," she said. "That little girl was me."

The exchange was even coordinated with a photo of her as a young girl, tweeted out by her campaign at the conclusion of her argument against the former vice president.

Biden didn't apologize, and he defended his record.

"It's a mischaracterization of my position across the board. I did not praise racists," Biden said. "I did not oppose busing in America. What I opposed is busing ordered by the Department of Education."

He took his own swing at the senator, defending his choice to become a public defender instead of a prosecutor. It was the only attack against Harris, who was able to go after the front-runner and avoid taking heat from any of the other candidates.

The moment set the senator from California apart in a crowded field, quieted the raucous stage and even seemed to surprise the vice president.

It also came on the heels of other strong moments for Harris.

"America does not want a food fight, they want to know how we put food on their table," she said at the beginning of the debate, breaking in over the incoherent shouts of other candidates as the moderators worked to regain control.

Though the line may not have been the most off-the-cuff, it did the job -- giving voters one candidate to focus on.

Targeting Trump

While Democrats on the first night seemed hesitant to make the night all about President Donald Trump, night two saw the field take full aim at the president, who loomed large even without being on U.S. soil.

Both Biden and Harris used the first chance they got to go right after the president in front of millions of voters watching around the country.

"Look, Donald Trump has put us in a horrible situation. We do have enormous income inequality," Biden said in response to his first question of the night.

And for Harris, the California senator turned a question on how Democrats would pay for their big-ticket plans, like student loan cancellation, free college, and healthcare, into a pointed attack on the Trump administration.

"I hear that question, but where was that question when the Republicans and Donald Trump passed a tax bill that benefits the top 1% and the biggest corporations in this country contributing?" Harris said.

Sanders also took a familiar line of attack when talking about the president, calling Trump a "fraud" who is "not standing up for working families."

With perhaps the least conventional strategy of the night for taking on the president, Marianne Williams addressed Trump directly from the debate stage, saying said she would "harness love for political purposes" to take down the incumbent. "I will meet you on that field, and sir, love will win."

Democrats only mentioned the president 14 times throughout the two-hour debate night on Wednesday. But on night two, candidates turned up the heat, calling out Trump 34 times.

Health care a defining issue in the primary

Mirroring Wednesday night, just two candidates among the 10 on stage raised a hand in support of eliminating private health insurance.

Harris, who wavered on the question in a CNN town hall over the winter, took the opportunity to make her position clear and raised her hand. Sanders, who wrote the Medicare for All bill introduced in the Senate, made his position doubly clear. He raised both hands.

The Democrats onstage Thursday wasted no time explaining their differences. Despite attempts from the moderators to change the subject, the first 30 minutes of the debate returned time and time again to a battle of ideas around health care and whether Americans would be better off with a completely government-run system or the option to keep private coverage.

Many of the candidates shared personal stories of relying on health care, from Buttigieg's experience with his father's terminal cancer to Biden's tragic loss of his wife and son in a car crash, as well as the death of his son, Beau, to cancer.

But Bennet, who said he sided with Buttigieg and Biden on keeping a private option available, has perhaps been the most directly affected by illness in recent months.

"I had prostate cancer recently, as you may know, and that's why I was a little late getting in the race," Bennet said. "And I feel very strongly that families ought to be able to have this choice. I think that's what the American people want."

But there was a clear and defining moment on health care. A moment where every candidate onstage was in silent agreement, hands raised in support.

The question: "Raise your hand if your government plan would provide coverage for undocumented immigrants."

Generational rifts

The age gap on stage Thursday night between the youngest and oldest candidate was almost 40 years. The 30-somethings and the 70-somethings aimed to prove their ages weren't a hindrance but actually an advantage.

For Sanders, 77, and Biden, 76, the argument was about the benefits of experience. For Buttigieg, 37, and Swalwell, 38, it was a push for a fresh set of ideas.

Swalwell drew the contrast with a story about being a 6-year-old at the California Democratic Convention over 30 years ago and hearing Biden speak.

"Joe Biden was right when he said it was time to pass the torch to a new generation of Americans -- 32 years ago. He's still right today," Swalwell said.

In response, Biden pointed out just how long he's been in the game.

"I'm still holding on to that torch -- I want to make clear to you," he said.

It was around that time in the debate that Buttigieg, who regularly talks about what the world will look like in 2054 when he is Trump's age, jumped in: "As the youngest guy on the stage, I feel like I probably ought to contribute."

In his closing remarks, Buttigieg asked voters to help him "deliver that new generation to Washington before it's too late."

But in a race where the incumbent is 73 and three front-runners — Biden, Sanders and Warren — are at least 70, candidates continue to push past attacks on age.

"It's not generational," Sanders said. "The issue is who has the guts to take on Wall Street, to take on the fossil fuel industry, to take on the big money interests who have unbelievable influence over the economic and political life of this country."

Biden, for his part, tried to turn the conversation from what the younger leaders on stage would do to what he has already done.

"We all talk about these things. I did it. I did it," Biden said at one point.

And yet, there wasn't a candidate on stage who didn't argue that there was more that needed to be done.

Buttigieg owns up to South Bend police tensions

The 37-year-old mayor spoke directly Thursday night when asked about the tense situation still playing out in South Bend after an African American man was shot and killed by a white police officer.

"I couldn't get it done," Buttigieg bluntly admitted right away when asked about the situation. The mayor added that his city "is in anguish" after the shooting death of Eric Logan by a white police officer, whose body camera wasn't turned on.

"The officer said he was attacked with a knife, but he didn't have his body camera on. It's a mess. And we're are hurting," the mayor added.

Fellow 2020 hopeful Rep. Swalwell jumped in a few minutes later arguing that if the bodycam wasn't turned on and that was policy, Buttigieg should fire the chief. The mayor responded saying that under state law, the shooting would be investigated and "there will be accountability for the officer involved."

Swalwell pushed back, and in one of the more tense moments of the debate said, "But you're the mayor, you should fire the chief if that's the policy and someone died."

Buttigieg did not respond, but stared down the congressman until Williamson took over.

ABC News' Justin Gomez contributed to this report.