John Courtney Murray, We Hold These Truths: Catholic Reflections on the American Proposition (Sheed and Ward 1960).
From the publisher: Murray's...disarmingly lucid and accessible prose has caused his book to be widely cited and celebrated, but it still is not well understood. He wanted to show how distinctively Catholic thought could illuminate the authentic American idea of liberty. . . . We Hold These Truths at least offers the hope that Catholic natural-law thinking can bring together the religious devotion and moral concerns of the evangelicals with the devotion to reason and concern for scientific truth of the secular humanists. It offers the hope of getting Americans really arguing again, of holding again the truth that they are capable of engaging in the dialogue about the human good that is the foundation of any civil and civilized moral and political life.
Note: Rowman & Littlefield Publishers, Inc. published a new edition of this book in 2005.