If I were an ambitious and canny Democratic politician right now, one with a sort of mid-level public profile, well known to activists if not the general public, I would start planning to make a big splash early this summer.

There is a real chance, still small but growing, that the national Democratic Party might need to shove aside Joe Biden and engineer the party’s presidential nomination for someone else. If so, the only way to do it while pulling the party together rather than splintering it would be to choose someone widely acceptable, but without the enemies a prior contender naturally makes during bitter party primaries.