Yesterday, Ben Smith doubted that a purality of Republicans truly question Obama's birthplace. Ben favorably quotes ABC pollster Gary Langer:
"I think these measurements are not really reflecting 'belief' in the true sense of the phrase," [Langer] said. "Many people are expressing their opinion rather than an assertion of factual reality. People who don’t like you are going to take an opportunity to send a message…. They’re simply taking advantge of an opportunity to express antipathy toward him."
I’d imagine that you could substitute virtually any name in the place of Mr. Trump or Mr. Obama — Bill Clinton, or Ronald Reagan, or Oprah Winfrey, or Dwight D. Eisenhower, or Mark Zuckerberg, or Sarah Palin — and find that at least a few Americans reported themselves to be “birthers.”
The incidence of birtherism also tends to be higher in automated surveys, like those put out by Public Policy Polling. That could be because automated surveys tend to draw a less representative sample, with more extreme partisans and ideologues than exist in the real world, or because respondents feel especially inclined to have “fun” with the pollsters when they just have to push buttons rather than talk to another human being.
Clearly, some people do believe the lies and distortions about Mr. Obama’s birthplace; I’m just not sure that the fraction is as great as overly-literal readings of these surveys might suggest.