Ronald Brownstein discovers that “the racial and generational difference in participation between presidential-year and midterm elections is long-standing; it’s the more recent divergence in preferences that has resulted in the GOP’s midterm advantage”:
[T]he turnout gap has already contributed to the whiplash nature of modern politics, with voters careening back and forth between the two parties. This instability has encouraged both sides to treat every legislative choice primarily as an opportunity to score points for the next election. Oscillation, in other words, has encouraged polarization.
But the best news for the Democrats is that, whatever happens this year, eventually demographic change will overwhelm the turnout gap.
While Millennials and minorities still participate at lower rates in midterms than in presidential elections, their presence is inexorably growing on both fronts: the minority share of the vote in off-year elections jumped from 14 percent in 1994 to 23 percent in 2010, and this year will likely come in somewhere between that figure and the 28 percent from 2012. If Republicans can’t attract more votes from the growing numbers of minorities, Millennials, and white-collar white women who have powered the Democrats’ success in recent presidential elections, demographics will ultimately threaten the GOP’s hold on the House, too. “Obviously the Democratic presidential coalition continues to expand,” notes Ruy Teixeira, a leading liberal analyst of voting patterns. “Eventually you reach the point where even turnout differentials aren’t enough to derail it.” That’s an encouraging long-term prospect for Democrats—but it may be cold comfort if lagging turnout among their best voters contributes to another brutal midterm this year.