Wednesday night's DNC debate in Atlanta lacked energy or candidate engagement that many anticipated. In previous debates the surging or front-running candidate found him/herself in the cross-hairs of their opponents. Former vice president Joe Biden was grilled by Sen. Kamala Harris over his record on busing. Sen. Elizabeth Warren's Medicare for All plan was attacked from all sides. Going into Wednesday night,  Mayor Pete Buttigieg, the current leader in Iowa, was expected to face that same level of scrutiny. Ultimately, though, even when goaded by the moderators to confront him, the most serious opponents of the South Bend mayor pulled their punches. 

However, this doesn't mean we didn't see any friction on the debate stage.  There was a concerted effort by the two African-American candidates in the race, Sens. Cory Booker and Kamala Harris, to put a spotlight on the role black voters will play in the race and to (subtly) raise questions about whether Biden and Buttigieg are worthy of their support.

The debate got off to a slow start. Maybe it was the hour (it didn't start until 9 PM EST). Or, the strain of the last two days of marathon impeachment hearings. But, no one seemed to be able to get into a groove or into the moment. As one Democratic strategist wrote to me that night, "feels like debating to be student body president." This strategist also argued that the candidates were missing an opportunity to frame the contest more broadly: "If I were advising one of them, I well may have told them: fuck the questions. Use most of them to take it back to Trump. To his corruption and what we're learning about it. To the imperative of getting him out of the White House and saving the country. I dunno, in the moment we're in. "

But, about three-quarters of the way into the debate, we saw sparks fly over an issue that is THE key question in Democratic circles: which of these Democrats can not only win African-American voters in the primary, but who can ensure that they turn out in November of 2020.

No Democratic candidate since 1992 has won the nomination without winning a majority of the black vote. And, many Democrats blame Trump's victory in 2016 on Hillary Clinton's failure to inspire and mobilize voters of color.

The exchange started with a question to Harris about her criticism of Buttigieg's outreach to African-American voters. NBC's Kristen Welker read aloud a quote of Harris that "the Democratic nominee has got to be someone who has the experience of connecting with all of who we are, as the diversity of the American people," and asked her what prompted her to say this.

Harris didn't directly confront Buttigieg, as she had Biden in that first debate. Instead, she pivoted to highlight the important role that black women play in the Democratic party and the respect that they deserve from a party that often takes them for granted. Black women, she said, are asking "Where ya been and what are you gonna do" for me: A subtle jab at Buttigieg's lack of long-time support or experience with the African-American community. She went on to note the importance of re-establishing the so-called "Obama coalition" — a short-hand term for younger people and people of color — for the general election. "The issue has to be, how are we going to win? And to win, we have to build a coalition and rebuild the Obama coalition. I keep referring to that because that's the last time we won."

Not much later, Booker made his case to voters of color. "I have a lifetime of experience with black voters," he said, "I've been one since I was 18."

He went on to say, "Nobody on this stage should need a focus group to hear from African-American voters. Black voters are pissed off, and they're worried. They're pissed off because the only time our issues seem to be really paid attention to by politicians is when people are looking for their vote. And they're worried because the Democratic Party, we don't want to see people miss this opportunity and lose because we are nominating someone that doesn't — isn't trusted, doesn't have authentic connection."

The 'focus group' line was a not-so-veiled shot at Buttigieg, whose campaign had conducted interviews with black voters in South Carolina earlier this year and tested how the issue of his sexuality fared with them.

But, like Harris, Booker didn't call out Buttigieg by name; instead, he went after the white candidate who does have significant support among black voters, especially those in South Carolina: Biden. By not supporting the legalization of marijuana, Booker argued, Biden was discounting the role that the war on drugs has had on black and brown Americans.

"And so these are the kind of issues that mean a lot to our community," Booker said. "We lost in Wisconsin because of a massive diminution — a lot of reasons, but there was a massive diminution in the African-American vote. We need to have someone that can inspire, as Kamala said, to inspire African-Americans to the polls in record numbers."

Biden responded by arguing that he was "part of that Obama coalition…I was picked as vice president because of my longstanding relationship with the black community." But, what will be most remembered from the exchange was his claim that he'd been endorsed by "the only African-American woman that's ever been elected to the United States Senate" (he has the support of former Illinois Sen. Carol Moseley Braun). That led Harris to quip "The other one is here," and left the former VP momentarily speechless, before he replied, "I said the FIRST one" (which the transcript shows he did not say).

The question going forward is whether Booker and Harris will continue pressing the case they made indirectly in the debate: that voting for Biden or Buttigieg risks alienating voters of color next fall. Biden's success in the primary relies on holding onto their support in South Carolina and the Super Tuesday states, and Buttigieg can't make it past Iowa and New Hampshire without improving his share of the African-American vote.

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