The root causes of Democratic Party infighting are ideological and political. If everyone agreed, they wouldn’t fight. But they disagree as to which ideas are good on the merits and which present the party in the best possible light. So they vie for primacy within the party.

But I would argue that the bitterness of it all arises from signaling decisions more than root disagreement. It’s not that progressives and centrists are incapable of understanding one another, or compromising, or making peace with policy difference—it’s that factional actors often go out of their way to dramatize differences for the broader public, and in doing so they behave like assholes.

On the progressive side of things, this manifests as implicit or explicit accusations of corruption. Democrats who aren’t on board with this or that expansive or structural reform have been captured by greedy special interests.

From the center it’s “hippie punching.” Moderates aren’t simply inhabitants of the political center, leading from the middle by example; they lay claim to the center theatrically, as if to say “unlike these crazies to my left…”

And my hypothesis is that Democrats could reduce internal temperatures dramatically by applying what I will call the CNN Town Hall test: Is what you say about your views how you would say it to a skeptical but sympathetic questioner asking you about it on live television?

MOULTON YOUR MOUTH

I’ve been thinking about this aspect of factional tension for many months, but wanted to flesh it out at greater length, because it’s ripe in the discourse again.

We can see in the cases of Nebraska’s Dan Osborn and Maine’s Graham Platner that left-wing Democrats will tolerate significant departures from progressive orthodoxy if they trust a candidate’s instincts and character. If they’re economic populists, they’re for the little guy, and if they’re for the little guy, we can trust that their regressive views on X, Y, and Z don’t arise from a corrupt or mean-spirited place.

They are not so generous with people like Seth Moulton, the Massachusetts congressman who’s announced a primary campaign against incumbent senator Ed Markey—a progressive in good standing. ...