From ages back, the idea of chronic know-nothings has re-emerged thanks to misperceptions that Barack Obama is Muslim (or wasn't born in the U.S., or perhaps isn't actually an Earthling at all). This NYTimes opinion piece does a nice job of summing up the topic about how we're building a nation of know-nothings.
Of course this is a topic near and dear to my heart, given I published an academic piece earlier this year attempting to explain who were the folks who, during the 2008 election, continued to doubt Obama's religious affiliation despite all information to the contrary. I love it when I'm far ahead of the curve. Happens, oh, once in a lifetime.