It won't.
The thing is, nothing will.
I know you've been espousing a kind of Green Lantern theory of turnout for a while, where if the Democratic party would just try hard enough they'd get the turnout they need, but seriously, everyone knows about this. The party and candidates have always sought higher turnout, shit, the success of the party depends on getting people out to vote. They are trying. It's good that they're trying, because that does get us votes on the margins. But the idea that there's some kind of magic formula that's going to entice everyone who is naturally in the Democratic constituency to show up for every election and vote the entire ballot is just wishful thinking.
A big part of it is that Democrats skew younger, and young people don't vote nearly as much because they aren't as politically engaged. Most young adults are busy getting their life sorted out, they've barely started dealing with many of the issues of adult life that state and local politics directly impact, so it's not even on their radar. At best they'll notice the Presidential election every four years because it's such a huge overextended media event. If we're lucky, there will be a charismatic enough candidate to drive up things on the margins. But midterms? Forget it.
This is democracy butting up against some of the limits of basic human nature. See also: impoverished people who are so fucking busy just trying to hold things together that they've got absolutely nothing left in the tank for political engagement. The Democrats being the party of the young, poor, and oppressed means that politics is simply going to rank lower on the list of things they have the time, energy, and will for than it does for the other side.
If we want everyone engaged, we'll need mandatory voting. That's all there is to it. Until then, politics has to compete with everything else in our overstimulating and exhausting society. And on the left side of things, that's a bigger problem that's not going to go away.
