A new CBS/NYT poll finds that 47 percent of Republicans think Obama wasn't born in the US. Another 22 percent aren't sure. Steve Kornacki says this "doesn't mean they've thought things through and believe an elaborate plot has been carried out, and it doesn't mean that being told actual facts about Obama's birth will sway them":

Trump's message may be resonating with so many Republican voters simply because it represents the most blunt and unrelenting attack on Obama's "American-ness" that they've heard from a major Republican. In other words, it may not be the specifics of Obama's birth certificate and hospital records that excite them; it's more the idea that someone so prominent is willing to stand up and take so much heat for saying, essentially, "Barack Obama isn't one of us."

And culturally he isn't. But neither is more than half the country. And they're all citizens. Many thought America could not elect a non-white president. They were wrong. It turns out America could elect a non-white president, but only with a hefty segment of the country denying his legitimacy.