It is very rare, if not unheard of, to catch a presidential candidate, especially a Republican, in the act of saying he or she would be willing to sign any tax increase that lawmakers wished for. But that's what happened to former Arkansas Gov. Mike Huckabee, who has rocketed to a statistical tie in Iowa with Mitt Romney, largely as a result of the former Baptist minister's support from evangelical voters in the nation's first caucus state. The Club for Growth, an effective tax-cut advocacy group, has been on Huckabee's back almost from the beginning of his candidacy, sending out...