In recent decades, the Republican party has been a vehicle — imperfect, like all human institutions, but serviceable — for promoting causes at the center of Catholic social concern in the United States: (1) providing legal protection for unborn children, the physically disabled and cognitively handicapped, the frail elderly, and other victims of what Saint John Paul II branded “the culture of death”; (2) defending religious freedom in the face of unprecedented assaults by officials at every level of government who have made themselves the enemies of conscience; (3) rebuilding our marriage culture, based on a sound understanding of marriage as the conjugal union of husband and wife; and (4) re-establishing constitutional and limited government, according to the core Catholic social-ethical principle of subsidiarity. There have been frustrations along the way, to be sure; no political party perfectly embodies Catholic social doctrine. But there have also been successes, and at the beginning of the current presidential electoral cycle, it seemed possible that further progress in defending and advancing these noble causes was possible through the instrument of the Republican party.