Detroit—Former Michigan governor Jennifer Granholm sighed after the second group of 10 Democratic presidential candidates finished the second night of the the second round of the exercises that the Democratic National Committee refers to as “debates.” “This was a joyless debate,” said Granholm. She was right. The front-runner, former vice president Joe Biden, took his expected hits on Wednesday night. The other leading contender on the stage, California Senator Kamala Harris, took some unexpected hits. Biden and Harris pushed back, sometimes effectively, sometimes not. But the second night of debating lacked the electricity, the energy, and the clarity of purpose that Massachusetts Senator Elizabeth Warren and Vermont Senator Bernie Sanders brought to the first.

Tuesday night’s vibrant ideological clashes, which saw the two progressive senators fend off “Republican talking point” jibes from debate moderators and centrist Democrats, gave that debate a coherence that was missing on Wednesday night.

The distinction was so clear that Yvette Simpson, the chief executive of the progressive group Democracy for America, said late Wednesday evening, “The real winner of tonight’s debate was Tuesday night’s debate.”

“On Tuesday,” Simpson explained, “Bernie Sanders and Elizabeth Warren not only delivered strong performances, they teamed up to articulate a bold, inclusive populist vision for the future of the country that Democrats need to beat Trump AND deliver a transformative win in 2020. We didn’t get that tonight.”

CNN’s Nia-Malika Henderson, a veteran reporter on Democratic presidential races, was blunter. As Biden, Harris, and the other Wednesday night debaters were busily trying to make cases that they had prevailed, Henderson calmly declared, “I think the real winner tonight was Elizabeth Warren. If you look back at her debate performance, I think she’s the best political athlete on the field.”

The dynamism of the first-night debate was so much greater than that of the second night that CNN’s Jake Tapper actually tried at one point to get Biden into a sort of debate with Warren.

“Vice President Biden, last night on this stage, Senator Elizabeth Warren said, quote, ‘We’re not going to solve the urgent problems that we face with small ideas and spinelessness. We’re going to solve them by being the Democratic Party of big, structural change,’” said Tapper. “What do you say to progressives who worry that your proposals are not ambitious enough to energize the progressive wing of your party, which you will need to beat Donald Trump?”

Biden’s answer was no answer at all. He seized on an earlier reference by Tapper to Trump’s narrow 2016 win in Michigan and talked about how Obama-era stimulus spending and “bailing General Motors out” had saved “tens of thousands of jobs here in this state.” True enough. But what Biden didn’t say was that after those interventions, the state backed the Republican nominee for president in 2016.

Had Tapper pressed Biden on that point, things might have gotten interesting. Unfortunately, the moderator veered off course and said, “Thank you, Vice President Biden. Senator Gillibrand, what’s your response?” New York Senator Kirsten Gillibrand had a good night Wednesday—as did New Jersey Senator Cory Booker—but she also avoided the core question.

Warren and Sanders couldn’t really be avoided, however. They hovered over Wednesday’s session. The moderators and the candidates frequently referenced their positions, and even their rhetoric. As Colorado Senator Michael Bennet was pushing back against a Medicare for All proposal that has been advanced by Harris, he found it necessary to announce that his own health care reform proposal was “totally different from the plan that Senator Warren and Senator Sanders” support.

Recalling the Warren-Sanders critique of the terms in which centrist Democrats have been attacking Medicare for All, Harris pushed back against Bennet: “We cannot keep with the Republican talking points on this. You got to stop.” Biden then defended his own approach by saying, “This is not a Republican talking point.”

The former vice president spent quite a bit of time criticizing the reform legislation that Sanders famously wrote. At one turn, he defended his claims about the cost of implementing Medicare for All by claiming that “Bernie acknowledges it. Bernie acknowledges it.”

That’s a debatable point. How debatable? We’ll get the answer to that question when the Democratic debates enter their next phase—perhaps in September, perhaps later—and Joe Biden and Kamala Harris finally find themselves on the big debate stage with both Bernie Sanders and Elizabeth Warren.