But the congested field is suffocating qualified aspirants who would otherwise find oxygen. It’s putting an extra premium on viral moments and supersize conceits. It’s privileging celebrity. All of that will factor into who prevails, and all of that is because of Trump.

“Electability” dominates Democratic voters’ thoughts, because many of them are more horrified by four more years of Trump than they were by four more years of his Republican predecessors.

And every Democratic candidate’s theory of the race is a theory of Trump, reflecting his or her analysis of how Trump pulled off his astonishing upset.

Did it indeed rest on embittered and economically vulnerable white men in the Rust Belt? Then his challenger must be able to speak to that demographic group. That’s an argument made for and by Buttigieg, Joe Biden, Tim Ryan, Steve Bullock and John Hickenlooper. Note that they’re all white men themselves. By this thinking, it’s potentially reckless, after Hillary Clinton’s defeat, to stage a rematch against Trump with a woman or a member of a minority group.