Opinion writer

Thursday’s debate provided the first time to see several top presidential candidates — former vice president Joe Biden, Sen. Kamala D. Harris (D-Calif.), Sen. Bernie Sanders (I-Vt.) and South Bend, Ind., Mayor Pete Buttigieg — as well as an assortment of lesser known and, in some cases, improbable figures face off on the same stage. The result was, at times, explosive and surprising, a tough contest between several tough competitors.

Harris, not unlike several middle-tier contenders last night, had the chance to mightily improve her standing (as former HUD secretary Julián Castro and Sen. Cory Booker of New Jersey did during Wednesday’s debate). And boy did she. She was the clear standout on the stage, mixing righteous anger, biographical stories and prosecutorial toughness. She demonstrated just how her toughness and prosecutorial experience could be wielded — not just against Democrats but eventually against President Trump.

From the first answer sketching out her economic plans to stepping in to chide her bickering colleagues (“America does not want to witness a food fight, they want to know how we’re going to put food on their table”), to a devastating attack on Biden’s record on busing (invoking her own experience as a child bused to integrated schools), to separating herself from the deportation policies of the Obama administration, and to chastising Buttigieg for not integrating South Bend’s police force, she was virtually pitch-perfect. Though she put up her hand for Medicare-for-all, she wasn’t grilled on details; instead, she told a story of mothers sitting in a parking lot afraid to go into the emergency room. By the end of the debate, I was left wishing for a Harris standoff with Elizabeth Warren.

Biden, after some miscues in the weeks leading up to the debate, had to show he was “with it” and ready for a rough-and-tumble fight. His strength is the amount he relishes taking on Trump — and getting under the president’s skin. He started capably by defending Obamacare over Medicare-for-all, and rattling off his plans on education. Ironically, it was Sanders not Biden who came under fire on policy grounds. With so many voices on the stage backing his public option, Biden never was directly challenged by Sanders on Sanders’s signature issue.

As the debate went on, however, the former vice president ran into trouble, most dramatically and painfully at the hands of Harris on the issue of race. Insisting that he favored letting localities decide on busing was a bad misstep because the discrimination at issue, in many cases, requires federal intervention. Biden soldiered on but real damage had been done. He defended his vote for the Iraq War and then pivoted to his positions on Afghanistan and pulling troops out from Iraq. He stumbled again, however, on guns — mangling a punchline when he said that our opponents were gun manufacturers and not the National Rifle Association. What Biden meant to say was that our opponents aren’t gun owners.

Mostly, he suffered in comparison to brighter, sharper voices. Was this fatal to Biden’s chances? No, but it suggested he is a very, very vulnerable front-runner. He also got lucky: Sanders had a poor night as well.

Sanders, after a solid performance last night from Sen. Elizabeth Warren (D-Mass.), needed to demonstrate that he could offer progressives something unique. He also entered amid grumbling that, as was perceived in 2016, he was not a Democratic Party team player. He was the old Bernie — yelling, stern and short on details. How do we get to Medicare-for-all? Everyone gets behind it! His free college plan came in for a pummeling by Buttigieg, who made clear we should not subsidize college for billionaires’ children. Sanders’s act wore thin as time went on. He was forced to admit that taxes would go up (though health-care costs would go down) under his Medicare-for-all plan, and struggled to explain how it would work on a national level if it could not work in any state. He did himself no good snapping at debate moderator Rachel Maddow, claiming that she had mischaracterized his record on guns when she had, in fact, quoted him.

For Buttigieg, the debate was a welcome interruption to a spate of unrelenting negative coverage of his handling of a police shooting back home that had only deepened his problem attracting African American votes. The South Bend mayor was on his game. He used personal details — his father’s death, his own student loan debt — to make his policy points. He was the only candidate to talk about making “not going to college affordable,” a smart point for the more than 60 percent of Americans without college degrees. He had a quintessential Buttigieg moment declaring that a party that identifies with Christianity but separates children at the border and puts children in cages “has lost all moral authority.” On China, which is using technology to create a dictatorship, Buttigieg urged us to invest in our own technology and infrastructure — a popular theme among Democrats. Then came the race issue. He tried simply confessing he hadn’t done enough to integrate the police force but was thrown off guard when Rep. Eric Swalwell (D-Calif.) told him just to fire the police chief. He did recover on foreign policy, effectively jabbing Trump by saying there’s no telling what country he’ll anger the most between now and Election Day.

Two Colorado moderates, Sen. Michael F. Bennet and former governor John Hickenlooper, needed to position themselves as plausible alternatives in the event Biden fizzles. Hickenlooper occasionally popped up, but Bennet was a consistently strong, but moderate voice. He stuck up for a public option, sounded tough on China and went after Senate Majority Leader Mitch McConnell (R-Ky.), gerrymandering and Citizens United. He also scored a direct hit on Biden after the former vice president bragged about rolling back the Bush tax cuts for the wealthiest individuals. Bennet interjected, “The deal that he talked about with Mitch McConnell was a complete victory for the tea party.” Bennet pointed out that the deal made the rest of the tax cuts permanent. “That was a great deal for Mitch McConnell. It was a terrible deal for America,” Bennet said. The former vice president had no response. If Biden sinks, Bennet is well positioned to move up as a moderate alternative. He spoke up for repairing our alliances and laid into Trump for losing credibility on the international stage.

Sen. Kirsten Gillibrand (D-N.Y.) and Swalwell, both competent Democratic lawmakers, had to show they were presidential material to maintain credible campaigns. Swalwell looked earnest but stiff and somewhat ill at ease. Gillibrand, when she could edge into the conversation, made her pitch directly to American women with strong statements on abortion rights, but frequently piped up with a reminder she had worked on one bill or another. If she can stay on the stage, she may have a chance to grow on voters and flesh out ideas like the Family Bill of Rights.

Marianne Williamson and Andrew Yang (albeit without putting on a tie), two non-politicians with not a ghost of a chance, wound up on the stage with actually plausible contenders. They were non-factors.

It bears repeating that we are more than six months before the Iowa Caucuses. Many of the candidates you saw on Wednesday and Thursday will have dropped out by then. Moreover, at that point, we’ll have watched debates in July, September, October, November, December and January, so, by then, voters may only dimly recall this week’s proceedings. Anyone who thinks the first round of debates was determinative should talk to Jeb Bush, who at this stage in 2015 sat atop the GOP presidential polls.

Thursday’s winners: Harris, Harris and Harris. Buttigieg except on race. Bennet.

Thursday’s losers: Sanders, Biden and Swalwell. Buttigieg on race.

Watch Jennifer Rubin’s picks from the first night:

Read more:

Alyssa Rosenberg: What Kamala Harris is asking of us is so much harder than a food fight

Highlights from both nights of the first Democratic debates

Fact-checking the first Democratic debates

Stephen Stromberg: The question that separated the serious from the ridiculous

Erik Wemple: An opinionated host moderated (another) presidential debate. The world remains intact.

Ed Rogers: Ranking the candidates in the second night of the Democratic debate

Alexandra Petri: Here are some true — and maybe true — statements about Marianne Williamson