As Kahan points out, it’s not just Republicans who don’t believe in evolution: most Democrats and Independents don’t believe in it either — unless you count those people who believe that there has been evolution that was guided by a “supreme being.” Yes, Republicans believe evolution less than Democrats do — but when you start looking at the numbers, the patterns claimed by Krugman start to fall apart. The percentage of Republicans who believe in evolution “due to natural processes” dropped a statistically meaningless 2 percentage points (from 23 percent to 21 percent) in the past four years, during which time the percentage of Democrats who believed in natural evolution increased by an even more meaningless 1 percentage point, and the percentage of Independents decreased by 3 percentage points. The big changes are in the proportion of Democrats and Republicans who express support for evolution guided by a supreme being, whatever that means.