In 2008, Democrats enjoyed a solid advantage in partisan identification. By 2010, that advantage had largely evaporated. As I detailed in a previous post, in every state, the Democratic partisan ID advantage has declined, and by an average of nine percentage points.
But the decline has not been equal across the nation. In fact, there is a good deal of variation in the change in Democratic identification across states, ranging from a ranging from a drop of 22.2 percent in New Hampshire (from +13.2% to -9.0%) to a drop of just 1.6 percent in Mississippi (see this table for state-by-state numbers).
Why should these changes vary so much from state to state? Are there demographics that might explain this?
As it turns out, the only statistically significant predictor of the decline in democratic partisan affiliation advantage is the percentage of white people in the state. Surprisingly, the state economy (at least as measured by unemployment rate or change in unemployment rate) doesn’t seem to matter.
Finally, we come to the share of white voters. Here we have a consistent pattern, and one that is statistically significant (and explains 13 percent of the state-level variation). For every ten percent increase in white voters as a share of the electorate, the predicted decline in Democratic ID advantage is almost one full percentage point (the one outlier in the lower left is Hawaii, which is highly Asian. Without that outlier, the relationship would be even stronger).
This re-emphasizes the problems that Democrats seem to be having with white voters. (Democrats have not enjoyed parity with Republicans among white voters in 20 years, but 2010 was especially bad, with white voters breaking 62-to-38 for Republicans in the mid-term elections.)
This explains why the Democratic decline in diverse states like California (47 percent white) and Nevada (66 percent white) is less than in lily-white states like South Dakota (90 percent white) and New Hampshire (95 percent white), even though California and Nevada have much higher levels of unemployment.
These results exist regardless of economic circumstances (these findings are robust even in a statistical model that controls for all the other possible factors discussed).
The brief summary of this analysis is that race may matter more than the economy for why voters have been identifying more and more as Republicans for the last two years.
Of course, there are obvious caveats to this interpretation, most significantly the fact that I am playing around with state-level data, as opposed to individual-level data.
But the patterns are discouraging for Obama and the Democrats. Much prognostication has argued that the number one factor for 2012 will be the unemployment rate, because historically, the unemployment rate has been a very strong predictor of whether the incumbent party wins or not. This analysis suggests that something else is going on as well. Democrats are having a hard time with seniors and particularly white voters, and it’s not just a story about the state of the economy. Democrats ignore these scatterplots at their peril.