In 2008, the first time that every American voter had a chance to vote for a Black man for President, there was a striking pattern. In some counties, white voters cast far fewer votes for Barack Obama than they had for previous Democratic candidates. For example, in Floyd County, in eastern Kentucky, white voters cast only about 49 percent of their votes for Obama, while, only four years earlier, they had cast 63 percent of their votes for John Kerry. This shift away from voting Democrat was seen in many counties across the United States. In fact, in many counties, Obama received a smaller share of votes than had any of the previous four Democratic candidates.

Of course, there are many reasons this could have happened. But given that the troubled presidency of GeorgeW. Bush and the 2008 economic crisis meant it was a favorable election year for Democrats, it seems likely that race may have played a role – that white people were driven away from their traditional party loyalties by a Black man on the ballot. We might imagine that if we had gone to these counties during the 2008 election, we would have found petty demagogues using race to stir up fear by implanting negative stereotypes of Blacks and of a Black president into the minds of white voters.

Some of these demagogues did exist, but in this book, we are searching for something more systematic, something that will affect voters’ attitudes and behavior regardless of the actions of any particular politician. Indeed, if we zoom out and look for patterns in the data, we see that in 2008, the demagogue was not any local politician, but rather geographic space itself. Looking across the country, we see that white voters in the most-segregated counties were between five and six percentage points less likely to vote for Obama than white voters in the least-segregated counties.