As she sees it, it isn’t quite right to refer to a Democratic or Republican “base.” Rather, there are Democratic and Republican coalitions, the first made of people of color, college-educated whites and people in metropolitan areas; the second, mostly noncollege whites, with a smattering of religious- minded voters, financiers and people in business, largely in rural and exurban counties.

“In the polarized era, the outcome isn’t really about the candidates. What matters is what percentage of the electorate is Republican and Republican leaners, and what percentage is Democratic and Democratic leaners, and how they get activated,” she said.
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[S]he maintains that actual swing voters are a small percentage of the result, even in counties where the vote swing is as large as Wasserman describes. Don’t talk to people in the bleachers of rallies; check the voter file, she says. “It would be one thing if that county had 100,000 people in it who voted in 2012, and then it was the same 100,000 who voted in 2016, but that is not what is happening,” she says. “The pool of who shows up changes.”
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But still, the results bore out her theory: For Democrats to win, they need to fire up Democratic-minded voters. The Blue Dogs who tried to narrow the difference between themselves and Trump did worse, overall, than the Stacey Abramses and Beto O’Rourkes, whose progressive ideas and inspirational campaigns drove turnout in their own parties and brought them to the cusp of victory.
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“I am arguing radical shit, OK?” Bitecofer told me over a series of phone calls over the past several weeks in her Virginia office. “What I am saying is that almost all of this shit is set in stone for three years, that almost none of the shit that people are hanging onto, in terms of daily articles, or polls, or the economy or incumbency or ideology is really worth that much.”