It was not Joe Biden’s worst debate, but neither was it his finest hour. Answering a question about foreign policy, attempting to attack President Donald Trump as simultaneously too hawkish and too dovish, as not possessing his uncanny ability to talk sense into the leaders of China and North Korea, Biden lost his train of thought—and then promptly blamed the moderator.

“Why am I stopping?” Biden asked. “No one else stops. Catholic school training.” Except this time the moderators didn’t really ask him to stop so much as he just trailed off mid-spiel. People have won South Carolina by yelling at the moderator before—think Newt Gingrich on the Republican side in 2012—but this didn’t feel the same. “You’re a gentleman,” CBS’ Gayle King reassured him. “Good home training.” MSNBC’s Chris Matthews also responded approvingly on Twitter.

South Carolina is probably Biden’s last stand. He is still clinging to his polling lead there, thanks to resilient black support, but Bernie Sanders is gaining on him quickly. Some polls also show Tom Steyer in the double digits, though Public Policy Polling offers a hopeful scenario for the former vice president—and maybe for the Democratic Party.

If Biden collapses, it is clear that a lot of centrist Democrats will gravitate toward former New York City Michael Bloomberg, appearing on the ballot for the first time next week on Super Tuesday and clearly motivated by a desire to stop Sanders from winning the nomination, at a brokered convention if necessary. And that might be something Democrats should want to avoid: a Bernie-Bloomberg race would be incredibly divisive for the party, which each candidate road-testing general election attacks against the other.

Yes, Elizabeth Warren’s attacks on Bloomberg remain the most pointed. But who does Sanders turn to when he needs a foil to show he’s not too sympathetic to the Chinese Communist Party? Bloomberg, the supposed centrist extolling the representative virtues of the accountability to the politburo. Who does Bloomberg say can’t win an election against Trump? Sanders, the current frontrunner for the Democratic nomination. This has the potential to make the unpleasantness between the Bernie Bros and Pete Buttigieg’s supporters look like a schoolyard brawl (Buttigieg’s husband, we should remind you, is an educator).

Biden for all his flaws could run a more dignified race against Sanders, should he survive South Carolina. Or he could continue to split the non-Left vote enough that Bloomberg’s machinations can’t deny Bernie the nomination in Milwaukee—an outcome that would divide the party more than any of the 2016 WikiLeaks revelations about the DNC.

Maybe Biden isn’t able to answer the call one last time. But the Democrats sure could use it.