Biden won in places where black voters make all the difference and in places where they don’t. He won in places — Massachusetts, Minnesota, Oklahoma — where he hadn’t even competed. He won Virginia by 30 points. He won Texas, where Sanders’s outreach to Latino voters was supposed to put him over the top. He won and won and won, taking the overall lead in the delegate count.

And his momentum may be even bigger than the Super Tuesday returns suggested, for three reasons. One, early voting in some states preceded his surge and probably didn’t reflect it. Two, the coalescing of other Democrats around him is so new that it may not have fully registered with voters. Three, exit polls affirmed that Democratic voters care more about choosing the fiercest adversary for President Trump than about embracing a candidate whose positions they like best. Super Tuesday cast Biden as that adversary. It gave him that glow. So he could shine brighter still when another six states vote in a week…

Sanders should be concerned — not just because Biden has staged an extraordinary comeback or because a Bloomberg exit would redound to Biden’s benefit. Sanders isn’t flexing the electoral muscle that he keeps claiming to have. In some states on Tuesday he did significantly worse than he had when he ran against Hillary Clinton in 2016, and this wasn’t the first time that his performance this year paled next to what he achieved four years ago.