I read yesterday that some 45-47% of Republicans believe that Obama was not born in the US and is not eligible to be President. Donald Trump's sudden surge in the Republican polls suggests that among the hardcore base, the number is far higher. Michelle Goldberg believes that this can only help the Democrats, and to a certain degree, I agree.
But that only works if the broad mainstream of America is actually skeptical. I am increasingly unimpressed with Americans' ability to process facts and evidence. The denial of evolution, climate change, or even economic realities of inequality--suggest that people believe what they want to believe, and to hell with the facts.