Last Tuesday evening I sat down to write a post conclusively showing that Democratic crossover voters couldn't have provided the winning margin for Dave Brat, the college professor who beat Eric Cantor in the Republican primary in an upset for the ages. It seemed pretty obvious, right? I mean, look at this graph by county:
Then a funny thing happened. As I entered precinct data for county after county, the opposite pattern kept popping up for individual counties, something that can be seen in maps of the results and Obama's vote share by precinct. And, not being a Republican, I had to revise my conclusions in the face of the data. In the end, the number of Obama voters who voted for Brat may have been greater than Brat's margin of victory.
So can we say crossover voters were responsible for Cantor losing? No, Cantor himself is where the responsibility lies. If he were popular among Republicans, instead of having just a 43 percent approval rating, we wouldn't even be talking about this.
But head below the fold to see just what kind of effect Democrats may have had on this race.
Update: New post-election poll confirms the calculations in this post.