Sen. Kamala Harris is the closest Democrats have to a potential consensus candidate. She doesn’t suffer from the enmity that Hillary Clinton voters have for Sen. Bernie Sanders, or that leftists hold for former Vice President Joe Biden, or that the Obama administration has for Elizabeth Warren. She’s not another white guy running to represent a diverse party. She’s got enough political experience to be a credible candidate, but not so much that she’s been on the wrong side of dozens of controversial issues.

But Harris wouldn’t be the first politician to look good on paper only to falter in the campaign. And so the question that has quietly suffused Democratic politics for the past few years has been: Can she do it? Can she perform under the lights?

Thursday night, she proved she can.

Harris won a debate over Bernie Sanders’s ideas despite Sanders standing right next to her. She looked like the heir to the Obama coalition despite the presence of Barack Obama’s vice president on the stage.

She tore into Biden’s comments about segregationists and his record on busing in a way that left him sputtering onstage, and that carried the meta-message that she’d be able to confront Trump with the same cool precision. She carefully criticized the Obama administration’s record on immigration in a way that showed she wouldn’t be hemmed in by the Democrats’ past. It was a command performance.

NEW: Kamala Harris crushed @IndivisibleTeam's flash poll of its members. n=4,500



Harris - 65%

Buttigieg - 15%

Biden - 7%

Sanders - 7%

Gillibrand - 2%

Bennet - 1%

Swalwell - 1%

Williamson -1%

Yang - 1%

Hickenlooper - 0%https://t.co/hrXUzOmMU8 — Alex Seitz-Wald (@aseitzwald) June 28, 2019

Harris took control of the evening early. The beginning of the debate was marked by the moderators asking Biden and Sanders questions that the candidates ignored in favor of canned statements. Harris went third.

“Do you think that Democrats have a responsibility to explain how they will pay for every proposal?” she was asked. Instead of ignoring the question to give the answer she wanted to give, she turned it back on the moderators to underscore her point. “I hear that question, but where was that question when the Republicans and Donald Trump passed a tax bill that benefits the top 1 percent and the biggest corporations?” She shot back.

About 20 minutes in, the debate devolved into an indecipherable shouting match. It was Harris’s voice that cut through the din. “America does not want a food fight, they want to know how we’re going to put food on their table,” she scolded. It’s a cheesy line, but she delivered it with authority. The rest of the candidates fell silent. The crowd cheered.

But it was in the middle of the debate that Harris changed the campaign. After Biden was confronted with a question about deportations in the Obama administration, Harris went where the other candidates had not. “This was one of the very few issues with which I disagreed with the administration,” she said, explaining that “as attorney general and the chief law officer of the state of California, I issued a directive to the sheriffs that they did not have to comply with detainers and instead should make decisions based on the best interest of public of the basis of their community. I was tracking it and saw that parents, people who had not committed a crime even by definition, were being deported.”

It was a gentle criticism of Obama, but a criticism nonetheless. And it presaged a much more direct attack to come. A few minutes later, in a discussion about Mayor Pete Buttigieg’s handling of a recent police shooting in South Bend, Indiana, Harris stopped the conversation. “As the only black person on this stage, I would like to speak on the issue of race.” Then she turned, unexpectedly, to Joe Biden.

“I do not believe you are a racist,” she said. “But” — you knew there was a but — “it was hurtful to hear you talk about the reputations of two United States senators who built their reputations and career on the segregation of race in this country. And it was not only that, but you also worked with them to oppose busing. And, you know, 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. And that little girl was me.”

Watch Kamala Harris confront Joe Biden on his record opposing federally mandated busing to integrate public schools: “That little girl was me.”#DemDebate2 pic.twitter.com/WXdvgs5zL0 — Vox (@voxdotcom) June 28, 2019

Biden’s answer was wan. “The fact is that, in terms of busing, the busing, I never — you would have been able to go to school the same exact way because it was a local decision made by your city council. That’s fine. That’s one of the things I argued for, that we should not be — we should be breaking down these lines.”

Harris wasn’t having it. “But, Vice President Biden, do you agree today — do you agree today that you were wrong to oppose busing in America then? Do you agree?”

“I did not oppose busing in America,” protested Biden, who very much did oppose busing in America. “What I opposed is busing ordered by the Department of Education. That’s what I opposed.”

“Well, there was a failure of states to integrate public schools in America,” Harris shot back. “I was part of the second class to integrate Berkeley, California, public schools almost two decades after Brown v. Board of Education. That’s where the federal government must step in. That’s why we have the Voting Rights Act and the Civil Rights Act.”

Kamala is going to have to prosecute herself for murdering Biden — Mike Drucker (@MikeDrucker) June 28, 2019

Harris, in a few unexpected moments, left Biden arguing the states’ rights position on busing. It was a devastating performance. And more important than the damage it did to Biden was what it said about Harris. If she could stride into the first national debate of her life and eviscerate Biden, then who’s to say she couldn’t do the same to Trump? It was her — not Biden, not Sanders, not Buttigieg — who you could most easily imagine taking on the president.

Harris walked into the debates an unknown quantity. She walked out the winner. Given the number of Democratic factions that could plausibly unite behind Harris’s banner, that’s no small thing. It’s a rare debate that truly shakes up the primary, but I suspect this one did.

A few other observations:

• Biden performed fine at first, and poorly as the night wore on. Toward the end of the evening, he was asked to answer for his support of the war in Iraq. It was a question he must have known was coming, but his answer was awful:

“Once Bush abused that power, what happened was, we got elected after that. I made sure, the president turned to me and said, ‘Joe, get our combat troops out of Iraq.’ I was responsible for getting 150,000 combat troops out of Iraq, and my son was one of them.”

So the case for Biden’s presidency isn’t that his foreign policy instincts are sound, but that Obama’s were?

Biden is supposed to be running as the heir to Obamaism, but he’s really running using Obama as a shield. He’s not the candidate onstage who sounds most like Obama; he’s the candidate hiding behind him. It’s a bad look, and it won’t work for long.

• The first debates showed both the victory Sanders has won and the difficulties it poses for his campaign. It was his ideas that set the terms of the discussion, from Medicare-for-all to free college. But unlike in 2016, when he had those policies to himself, most of the 2020 candidates have either adopted his plans or come up with specific counterproposals meant to highlight their weaknesses. That’s left Sanders competing stylistically and ideologically with candidates who have adopted his best ideas but bring other advantages to the table.

Warren and Harris, in particular, have left Sanders little room on the left, but Warren brings a wonkish command that Sanders has never quite had, while Harris is an African American woman running to represent a party that’s heavily female and nonwhite. Sanders performed fine, but he didn’t stand out the way he did in 2016.

• Buttigieg is a natural debater, and he offered about as good an answer on the South Bend shooting as was plausible, but it’s always hard to run for president from a place of apology. His bigger problem, to my ear, was the absence of an overarching theory connecting his answers. His responses are strong on their own terms, and I particularly appreciate his insistence that he’d prioritize restoring American democracy in his first year, but he’s offering individual answers rather than a clear message, and that’s tough in a field this big.

• Marianne Williamson’s presence on the stage was delightfully weird. Should she be president? No. Was the debate a bit more entertaining for her presence? Sure.