It’s still very early, but Joe Biden has emerged as the clear front-runner for the Democratic nomination. Bernie Sanders is in second place, although he appears to be fairly far behind, and one poll shows him in a statistical tie with Elizabeth Warren. So what should we think about the men currently leading the field?

Well, I have concerns. Not about electability, a topic about which nobody knows anything. Never mind what today’s general election polls say: What will polling look like after the inevitable Republican smear campaign? The answer to this question depends, in turn, on whether news organizations will cooperate with those smears as gleefully as they did in 2016.

No, my concerns are about what will happen if either man wins. Are they ready for the political trench warfare that would inevitably follow a Democratic victory?

The trouble with both Biden and Sanders is that each, in his own way, seems to believe that he has unique powers of persuasion that will let him defy the harsh reality of today’s tribal politics. And this lack of realism could set either of them up for failure.