There have been two story lines this year that offer contrasting impressions about what’s likely to happen in the November battle for control of the U.S. House: One is a seemingly unending string of big-time performances by Democrats in special elections (including the one earlier this week in Arizona). The other is a Democratic advantage in the generic congressional ballot (a polling question about party preferences in House elections), which is a shadow of what it was at certain points last year.
Nate Silver posed the problem directly after the Arizona results:
The bigger question is what to make of the disparity between the overwhelming swing toward Democrats so far in special election results — which would imply a Democratic wave on par with the historic Republican years of 1994 and 2010 — and the considerably more modest one suggested by the generic congressional ballot, which shows Democrats ahead by only 7 points and implies that the battle for House control is roughly a toss-up.
After musing that maybe the generic ballot was a lagging indicator that might change as November approached, Silver essentially concluded that both special elections and generic ballots were data points that should both be considered, instead of choosing one exclusively.
Cook Political Report’s Amy Walters is looking at the same question:
If a so-called “blue wave” is about to hit in 2018, why isn’t the generic ballot showing a bigger margin for Democrats? The latest Real Clear Politics average shows Democrats with a 6.5 percent lead. The FiveThirtyEight.com average has Democrats with a 6.9 percent lead. If Democrats are cruising to victory in the fall, why does the generic not look more like it did over the summer when it showed Democrats with a double-digit lead?
Like Silver, Walters figures the numbers may turn bluer later this year. But she has a specific theory for why that could happen: the bulk of the “undecided” generic vote is among self-identified independents, and “here’s what we know about them: they don’t like Trump.”
In the latest Marist/NPR/PBS poll (April 10-13), for example, Trump’s job approval rating among independents is 38 percent. On the generic ballot question in that same poll, the congressional Republican gets 32 percent of the independent vote. A late April Quinnipiac poll showed Trump with a 33 percent job approval among independents, and 36 percent of independents say they will vote for a Republican in the fall.
As more independents begin to make up their minds about their midterm choices, their anti-Trump leanings will probably push up Democratic margins — an anti–White House dynamic that tends to happen during midterms anyway.
Both Walters and Silver also think the superior Democratic enthusiasm so evident in special elections hasn’t fully manifested itself in generic polls at this point. As Nate puts it:
One plausible answer is that the generic ballot will shift further toward Democrats once voters become more engaged with the campaign in their respective districts and pollsters switch over to likely voter models.
Now that’s certainly a switcheroo from the 2010 and 2014 midterms, when the shift to likely voter screens usually boosted GOP margins. But that does raise one point of caution about assuming Democrats will benefit from the same dynamics this November: the kinds of people who currently tend to vote Republican — older and whiter voters — have eternally been more likely to show up for non-presidential elections than the kinds of people who currently tend to vote Democratic — younger and minority voters. It’s so familiar a phenomenon that there’s a name for it: the Democratic “midterm fall-off” problem, which has been exacerbated by this decade’s exceptional polarization of the electorate by race and age.
It’s pretty clear by now that Democrats have found at least a temporary solution to the “midterm falloff” problem, and his name is Donald J. Trump. But there remain two questions: will the enthusiasm among Democrats he has created totally erase the traditional disparities in non-presidential turnout? And does the evidence that it has in so many special elections since Trump became president mean we can assume it will carry over to a regular midterm election, when Republican turnout will likely return to its “normal” levels?
As November approaches, all these mysteries will be answered, but for now, Democrats should be both excited and wary.