Trump’s latest woes and outbursts, combined with the ambivalence of Republican leaders in defending him, further serves to brighten Democratic prospects both in November and in 2020. But will Democrats fall into their too frequent habit of screwing up a sure thing?

The Dems’ problem might be described as an embarrassment of riches—too many aspiring presidential candidates. And too many progressive ones.

What’s wrong with a bumper crop of progressive candidates? They could splinter the progressive field, allowing a centrist to win the nomination, weakening the Democrats’ pocketbook appeal against Trumpism.

Nobody is going to declare for president before this November’s election, of course. But my sources all tell me that Elizabeth Warren, Bernie Sanders, and Sherrod Brown are all likely to get in.

If one of these ran and the others stayed out, that candidate would have overwhelming grass roots support and would win the nomination. If all three get in, that could be a disaster.

What’s needed is a kind of pre-primary progressive primary, in which the weaker two candidates agree to withdraw in favor of the leader. The trouble is that there are no smoke-filled rooms anymore and no strong party figures to broker such an agreement. (Memo to Rich Trumka: this could be you.)

So with the most momentous presidential election maybe since 1860, there is a risk that the overwhelming progressive mood of the Democratic party base could founder on a fractured field.

Ideally, the three candidates themselves might make such an agreement, but that’s a long-shot. Or all three might take a closer look, and one or two might decide not to run.

History turns on the vagaries of such details. Let’s hope the progressive candidates find a way to avoid doing each other in.