What rich irony, if one of the most calculating politicians in modern American politics miscalculated the will of Wisconsin's Republican voters, something Democrats have done repeatedly since 2010. If Donald Trump loses Wisconsin's primary on Tuesday, it will not be because of the uproar over his comments about Ted Cruz's wife, Heidi. Or his reaction to the confrontation with a female reporter that led to an arrest summons for his campaign manager. Or even his suggestion that women who get abortions should face “some form of punishment” if Roe v. Wade is overturned. Instead, it will be his misunderstanding of...