Cardinal Ratzinger, acting with the expressed approval of Pope John Paul II, is to be commended for clarifying a troubling aspect in American politics that may turn out to be decisive in next year's presidential campaign. Last week, he issued a document stating unequivocally that "The Catholic lawmaker has a moral duty to express his opposition [to homosexual marriage] clearly and publicly and to vote against it." The statement made clear that "There are absolutely no grounds for considering homosexual unions to be in any way similar or even remotely analogous to God's plans for marriage and family." As defined...