This article investigates the influence of religious values on domestic social policy-making, with a particular focus on Catholics. We analyze roll call votes in the 109th Congress and find that Catholic identification is associated with support for Catholic Social Teaching, but both younger Catholics and Republican Catholics are found less supportive. In followup interviews with a small sample of Catholic Republicans, we find that they justify voting contrary to Church teaching by seeing its application to domestic social issues as less authoritative than Church moral teachings on issues like abortion.