“The fallacy that President Obama is a Muslim has tripped up many a politician,” said NPR’s Jessica Taylor hopefully on Friday, “and on Thursday night, GOP presidential front-runner Donald Trump was its latest victim.” Trump’s presumed faux pas was his failure to correct a questioner who asserted that Barack Obama was a Muslim. Taylor’s real error as a reporter, like that of all her mainstream colleagues, was to dismiss the questioner’s assertion as a “fallacy” without providing any evidence to the contrary. Strange but true, reporters pride themselves on knowing nothing about Obama’s roots. Last month, for instance, Catherine Thompson...