It is now official: 25% of Americans are not just stupid, but plain wrong. When push came to shove, Mr. Obama, born in Hawaii in 1961 (making him 50ish), today produced his full birth certifcate, immediately rendering the "Birther Movement" null and void; it has long been inane. Where does this leave a quarter of all Americans? Those too dumb to face facts? Well, for a start, they can continue to think that Donald Trump is a model of good citizenship.