Moderate Democrats have been consistently inconsistent for decades. They have been rightfully critical of the prospect of a progressive presidential nominee: A progressive could alienate centrist voters, drive up voting rates of conservatives, and imperil the reelection chances of House Democrats in districts Trump won in 2016. Moderate Democrats have wrongfully refused to be self-critical of the prospect of a moderate presidential nominee: A moderate could alienate progressive voters into not voting or voting third party, drive down the voting rates of the party’s younger and nonwhite base, and fail to win back young or liberal white working-class swing voters who swung from Obama in 2012 to Donald Trump in 2016. To be a progressive in a party with a moderate is like being on a team with someone who sees all your deficiencies and does not see any of his own deficiencies, who always takes the credit when he wins, and never accepts blame when he loses.

The critic’s refusal to self-critique is the tragic enigma of the moderate Democrat: It could cost the Democratic Party the most consequential presidential election in recent memory. Moderate Democrats have lost presidential elections again and again, even as the doctrine of the electable moderate wins Democratic primaries again and again.

I not only fear a moderate Democrat losing to Trump in November; I fear moderate Democrats refusing to accept blame for the loss.

My fears are rooted in what the doctrine of the electable moderate conveniently misses: the critical importance of the other swing voter in swinging elections in the 21st century.