This paper analyzes in comparative key, the trajectory of the Chilean and Italian Christian Democratic parties in the second half of the twentieth century, paying special attention to the impact that changes in the agenda of the Catholic Church had on the fortunes of this political actor. The analysis begins with the postwar years, when the Church developed a concern about an atheistic Marxism that challenged catholic views of society; as a consequence, the Church established a special relationship with Christian Democratic parties. Then, the paper describes the political impact of the second Vatican Council. Finally, the paper considers Church's recent emphasis on individual morality as well as the adoption of forms of political action akin to pressure groups. The comparative analysis shows the similarities of the Italian and Chilean cases regarding the left and right-wing alignments facing religious matters. The analogies help us to understand the identity crisis which affects, in both cases, Catholic political groups which converged to center-left coalitions.