How Was an Obscure Legal Concept Transformed into the Essence of Judaism?

The Hebrew phrase tikkun olam—“fixing the world”—has come to be one of the most well-known concepts in American Judaism, cited even by the President. In the Talmud, the term refers to adjustments in Jewish law made to benefit the workings of society. Medieval and Renaissance kabbalists then reinvented the term to refer to a mystical correction of the cosmos. In the 20th century, the term took on a whole new life, becoming a catchall for social and political activism usually of a leftwing variety. Jonathan Krasner surveys the history and examines what it says about the evolution of Judaism in America: