Many Democrats believe in the “turnout myth” (full disclosure, I used to myself). The myth runs as follows — “triangulators” such as Clinton and Obama run on moderate platforms to capture the moderate vote, but in doing so they lose the excitement of the liberal wings of their party, and ultimately end up with less votes because of depressed base turnout.
As an example of how this could work, liberals point to Republicans, who are said to run more base-focused elections than Democrats and benefit from that. A short tour of the math, however, shows that Democrats can’t afford to sacrifice the middle for the edges.
Self-identified liberalism is growing in America, but still polls at a fraction of support for conservativism.
One way of looking at this: to get to 50% support Democrats have to capture a whopping 75% of the moderate vote, while Republicans only need to capture a small fraction (25%) of the moderate vote to win.
Could base turnout overcome this disadvantage? For Republicans, yes. For Democrats, no. A reasonable increase of turnout in an election might push participation up by 5% in that demographic. The “youth wave” in 2008, for example, was an increase of about 4 percentage points of the under 30 vote, breaking 66/31 for Obama.
In practice, this wave of turnout represented one percentage point in the final results — an increase from 17% of the total vote to 18% of the total vote, and was worth less than one percent of advantage to Obama.
In close elections, that percentage point can make a world of difference, but for Democrats it can only do that if going after that vote does not sacrifice moderate support and turnout. For Democrats, a five percent increase in liberal turnout can be offset by a mere 3.5% decrease in the moderate vote. For Republicans, the opposite is true: an increase in the conservative vote more than offsets losses in moderates, because there are more conservatives than moderates in America.
This is why, despite what we might want, the winning national strategy for the Democratic party has been to run a center-left campaign in a center-right nation.
That’s not to say it’s hopeless to get to further to the left: you’ll notice that slow drift up in self-identified liberals. That drift up largely comes from our party and elected Democrats making the case for liberalism. As we win elections and talk like Democrats we demonstrate that liberalism works. But we do that by getting in office and showing what good governance looks like. We build that narrative with each election we run, but particularly with each person we get in office to demonstrate liberalism in action. Eventually self-identified rates will be high enough that we can run much further to the left. But that time is not now.