Suffering a heart attack the previous week would not normally be seen as the best preparation for a presidential debate. It did not seem to do Bernie Sanders any harm. Having been all but discounted from the Democratic race, the 78-year-old outperformed his fellow debaters on Tuesday night in Ohio — most notably the frontrunners, Elizabeth Warren and Joe Biden.
The Washington Post revealed that Mr Sanders had also picked up the endorsement of the Democratic party’s youngest star, Alexandria Ocasio-Cortez. If the 30-year-old Ms Ocasio-Cortez’s contrasting youth does not inject energy into the senator from Vermont’s campaign, the grassroots popularity of the congresswoman from New York will surely help.
All of which complicates the dynamics of the race. Tuesday night’s chief loser was Mr Biden, 76, who managed to appear older than Mr Sanders in spite of his seemingly good physical health. This was billed as Mr Biden’s moment to hit back at Donald Trump’s attacks on his son, Hunter Biden, whose business record prompted the US president’s allegedly impeachable attempts to extort the Ukrainian government.
Mr Biden muffled his lines. The former US vice-president also confused Hunter with his late son, Beau Biden, when he said he was proud that his son had been attorney-general of Delaware. Things did not improve from there. Mr Biden has now raised doubts about himself at each of the four presidential TV debates. It is no longer a question of when he will bounce back but whether he can.
Ms Warren ought to be the beneficiary from the rising doubts about Mr Biden. The most positive aspect of her debate was the fact that almost everyone else on the stage targeted her. They mostly left Mr Biden alone. That cemented her frontrunner status. But she did a poor job at defending it. The senator from Massachusetts again failed to concede that Medicare-for-all would entail across-the-board tax rises, prompting attacks from most of her rivals, including Mr Sanders, who owned up to the tax implications of a plan he originally popularised.
As the leading left candidate, as well as the frontrunner, Ms Warren probably expected to secure AOC’s backing. The fact that she did not will make it far harder to hoover up Mr Sanders’ share of the liberal base, which will be critical to her chances.
The Democratic race is now at an awkward juncture. Neither of the frontrunners look secure. But it is hard to see who would beat them. Kamala Harris, the senator from California, persists in miscued stabs at populism, such as her proposal to ban Mr Trump’s Twitter account. Beto O’Rourke, the Texan former congressman, is basically a single-issue candidate for banning assault weapons. Cory Booker, the former mayor of Newark, is preaching a Kumbaya togetherness that sits ill with the party’s temper. And for all his intellectual skills, Pete Buttigieg, the 37-year-old mayor of South Bend, Indiana, seems too young for people to imagine him in the White House.
Of the second-tier candidates, Amy Klobuchar, the senator from Minnesota, made the best audition to fill Mr Biden’s centrist shoes on Tuesday. But she, like the others, is nowhere near double digits in the opinion polls.
The left field is less crowded. But the dynamics are similar. It is very hard to imagine that Mr Sanders could become the Democratic nominee. The odds are stacked against elderly socialist heart patients. But he is strong enough to make life difficult for Ms Warren. Having come close to depriving Hillary Clinton of the nomination in 2016, and wounding her in the process, Mr Sanders is threatening to make Ms Warren’s journey just as hard.