How has American Catholicism interacted with American legal culture? Legal scholars have often examined this question in the context of contraception and abortion debates. This article focuses instead on the so-called Catholic left that emerged in protest against the Vietnam War in the late 1960s, and thereby seeks to bring the rich history of Catholic radicalism and peace activism into closer conversation with legal history. Drawing on both primary sources and a rich body of secondary literature in religious and social history that legal scholarship has not fully incorporated, the author examines ideas about law within the writings of Catholic left figures, including writer-monk Thomas Merton, sociologist-priest Paul Hanly Furfey, and activist-priest Berrigan brothers. Building on work by religious historians who have interpreted the Catholic radical tradition as a distinctive response to the limitations of political liberalism, this author emphasizes that the Catholic left also expressed a profound alienation from legal liberalism, with its veneration of lawyers and its faith in courts as sites of social progress. Revisiting the Catholic left through the lens of legal history raises questions for future research about the possible connections between leftist antiliberalism and the more familiar Catholic tradition of conservative illiberalism.