Sen. Kamala Harris of California went all in on every level Thursday night, taking a Democratic presidential contest that has been relatively well-mannered and turning it electric and confrontational. She already had the best performance of the night with a series of fluent and passionate statements before she took on former vice president Joe Biden on racial issues. Having underperformed after a strong start to her campaign, she gambled that pressing her advantage by attacking the front-runner would move her toward the front of the pack.

In the short run, her gambit will work. She is likely to be the center of attention for at least the next week, and, having been running mostly in single digits, she put herself on the same level as the front-runner.

Much will depend over the longer run on how Biden treats the episode. Can he find a way to get by the issue of race that he opened by reminiscing about two segregationist senators as part of his argument that he can work with anyone? How much time will he have to spend defending his past position opposing school busing? And will any of this undercut his polling strength among African Americans?

On the other side, will there be any reaction among Democratic voters against the first candidate in either debate to engage in serious verbal aggression against one of their party’s own?

Biden bristled at Harris’s attack, raised his voice and pushed back hard but somewhat impatiently. His answer on school busing seemed to be an endorsement of states’ rights. In replying to Harris, he got stronger as he went on, but then seemed to throw in the towel by ending an answer saying he had run out of time — when no one had yet called time.

For Harris, the attack on Biden served two particular purposes. Biden’s polling strength depends upon African American voters, the same voters Harris needs to prevail in the pivotal South Carolina contest. And if the race ever comes down to a more progressive candidate (presumably Sen. Elizabeth Warren or Sen. Bernie Sanders) against a more moderate candidate, Harris needs to nudge Biden aside to emerge as the middle-of-the-road choice.

She will also need to pass South Bend, Ind., Mayor Pete Buttigieg, who also had a strong — if less explosive — evening. He forthrightly took responsibility for his failure to expand the share of his city’s police force that is African American and spoke in earnest tones about the fatal shooting by police of an African American resident in his city. And on issue after issue, from guns to China’s use of technology to strengthen its dictatorship, he was clear, fluent and forceful.

He also offered two of the night’s more interesting lines: “If more guns made us safer, we would be the safest country on earth.” And, unpredictably during a conversation of college affordability, he said: “It also needs to be more affordable in this country to not go to college,” by way of arguing that those without higher education should have access to good jobs and good pay.

And he once again spoke as a Christian, accusing the Republicans of hypocrisy: “For a party that associates itself with Christianity, to say that … God would smile on the divisions of families at the hands of federal agents, that God would condone putting children in cages has lost all claim to ever use religious language again.”

It was striking that Sanders simply seemed to pick up from wherever he had left off in the last debate of 2016. He made the same arguments with the same affect and same list of villains. He spoke to the faithful. It was not clear that he gained any new ground. His support for Medicare-for-all dominated the debate for so long in the early going that what was supposed to be an encounter among potential presidents seemed to be a seminar on health care. Over both nights of debating, single-payer insurance proved itself to be the issue that will divide these candidates again and again.

Two other candidates — Sens. Michael Bennet of Colorado and Kirsten Gillibrand of New York — clearly made their presence felt, but their efforts were largely lost in the Harris-Biden fireworks.

The contrast between Wednesday and Thursday’s debate could not have been sharper. With Warren the only leading contender on the stage, Wednesday was a serious, substantive and relatively subtle struggle for attention, with Warren maintaining her leading position and former HUD secretary Julián Castro, Sen. Amy Klobuchar of Minnesota and Sen. Cory Booker of New Jersey strengthening their positions. But consensus and comity disappeared on Thursday — the debate that will be remembered as Biden’s first hard test and Harris’s prosecutorial moment.

© 2019, Washington Post Writers Group