An air of desperation suffused the Democrats' presidential debate almost from its first moments Tuesday night as six of the candidates confronted a reality they had previously tried to wish away: The seventh, Sen. Bernie Sanders, was on the verge of beating them all.
As recently as their last debate less than a week ago in Las Vegas, most of the rivals treated Sanders gingerly and focused their fire on former New York Mayor Michael R. Bloomberg. Sanders responded by clobbering his rivals in Nevada's caucuses and pouring resources into Saturday's primary in South Carolina and next week's 14-state Super Tuesday contests with a goal of putting a swift end to the nomination fight.
Having come close to booting away the prize most of them have spent more than a year pursuing, the other Democrats lost little time Tuesday in making clear that Sanders -- his positions, his judgment and his experience -- would be the prime topic of the night.
But while their efforts gave the debate plenty of passion, and may have planted doubts in the minds of some voters toying with supporting the Vermont senator, they did nothing to resolve the biggest problem the non-Sanders candidates face: Too many of them have stayed in the race too long.
Sanders began this year's campaign with one great strength -- the loyalty of his supporters on the party's left, many of whom backed him in his campaign against Hillary Clinton four years ago. That backing has never wavered and has allowed him consistently to win the support of somewhere between a fifth and a quarter of Democratic voters.
In a two-person race, support from one quarter of the voters is a recipe for failure. But as President Trump showed in his race for the Republican nomination in 2016, a committed minority can be the ticket to success so long as your opponents divide the opposition vote.
Sanders' opponents have done just that: All agree that some among them should quit the race, but none believe that he or she should be the one to do it. Over the last several months, they compounded Sanders' advantage by largely deciding not to challenge him, mostly giving him gentler treatment than his rivals endured.
Former Vice President Joe Biden, as the presumed front-runner for much of the year, came under sustained attack during several debates. Those criticisms and his sometimes-halting responses clearly damaged his campaign.
Sen. Elizabeth Warren of Massachusetts, whose standing rose steadily last spring and summer, got intense pressure in the fall to specify how her proposed healthcare plan would work -- and how she would pay for it -- even as Sanders largely skated by with bland admissions that he hadn't put forward any similar accounting.
Other candidates, like California Sen. Kamala Harris, endured scrutiny over previous parts of their careers -- years as a prosecutor in her case. That eventually helped push her out of the race.