Darwin Fish

A plurality of Republicans now believe that humans and other living things have existed in their present form since the beginning of time, according to a new Pew study. That’s 48 percent of them, compared with 43 percent who believe life forms have evolved over time.

What’s particularly remarkable is how quickly the party has shifted on this issue. Just four years ago, Republicans accepted evolution by a margin of 15 percentage points, 54-39. Meanwhile, Democrats have increased their margin of belief in evolution by six points, from 64-30 to 67-27. The overall point differential between the two parties has thus gone from 19 to 45. Independents, meanwhile, have stayed within the margin of error, remaining just about as pro-evolution as the Democrats.

So what happened to the Republicans?

A simple demographic explanation would point a finger at white evangelicals. In 2009, Pew found 57 percent of them disbelieving in evolution. That number has now increased to 64 percent. Given the disproportionate presence of white evangelicals in the Republican Party — they constituted 40 percent of the Romney vote in 2012 — this would account for roughly one-third of the shift in party views.

As for the rest of the shift, my conjecture is that Republican identity has increasingly come to be associated with the most conservative religious viewpoint on the full array of cultural issues — be it abortion, same-sex marriage, physician-assisted suicide, evolution, you name it. If you’re a Republican, that’s the program you’ve got to be with.