Richard Cohen: On Sunday, ABC's George Stephanopoulos asked former Arkansas governor Mike Huckabee, suddenly and ominously the front-runner in Iowa's GOP contest, whether Mitt Romney is a Christian. Mike Huckabee knew precisely what was being asked of him, and he also knew, because he is a preacher, what the right answer should be. But Huckabee merely smiled that wonderful smile of his and punted.
