Third, the importance that Democratic voters attached to “electability” and to beating Trump may have made them more willing to take cues from the establishment. Electability is a whole subject unto itself that I’m not going to do justice to here. I do think electability may be a teensy, tiny bit overrated as a reason for why Sanders lost. While perceptions of electability probably hurt Sanders relative to Joe Biden, it also probably helped him relative to candidates who weren’t white men: most notably, Elizabeth Warren.

Still, electability was important. In that Michigan exit poll, 58 percent of Democratic voters said they preferred a candidate that could beat Trump to someone who agreed with them on the issues — and 62 percent of the “beat Trump” voters went for Biden.

Fourth, Democratic party elites had an opportunity to learn from Republicans in 2016, and this may have made them more aggressive in backing Biden after South Carolina. One reason to be careful of declaring a “new normal” in any trend involving human behavior is that humans have an opportunity to learn from what happened last time and change course. The establishment’s failures in 2016 may have made partly elites reluctant to weigh in early on in the race this time around. But once they perceived Sanders as the true front-runner after Nevada, and Biden began to gain a little bit of momentum as he surged to a lead in South Carolina polls, party elites got behind Biden at extremely rapid rates. It’s hard to know if this would have played out the same way if there wasn’t 2016 to learn from.