Robert Houghwout Jackson was a justice of the United States Supreme Court during the years of World War II. This article considers his great but potentially perplexing December 1944 dissent in Korematsu v. United States, in which he refused to join the Court majority that proclaimed the constitutionality of military orders excluding Japanese Americans from the West Coast of the United States during the War years. This article considers Justice Jackson's Korematsu dissent in full. It was and is, contrary to some of the criticisms it has received over the past 60 years, a coherent position. Jackson's dissent is also biographical and, to that extent, deeply and personally pragmatic. It emanated in part from his outlook and upbringing as quintessentially a rural American civilian who viewed life as pacific and individually autonomous, and who saw our law as most workable in such times of peace and unthreatening personal freedom. It was grounded as well in his very special, direct, and formative experiences with executive power. Jackson's Korematsu dissent also fit into his general view of people and power and into what he saw throughout his life as the idea of law itself: it is the codified product of human beings struggling, by employing their rational and selfless capacities, to impose some limits on what they and their governments otherwise could perpetrate with the vast powers they possess. Justice Jackson's dissent in Korematsu v. United States merits its very high place in both the American legal and the human canons.