Without a formal enforcement mechanism, the Supreme Court of the United States is dependent upon its legitimacy to enact its rulings. Traditionally, the Court’s legitimacy is thought to be linked to its status as a legal, nonpartisan, and principled institution, making the politicization of the Court a threat to its institutional standing. This thesis examines the period of intense judicial politicization under the Obama and Trump administrations to determine how the Court’s legalistic reputation and legitimacy are viewed by policymakers and the American public. I begin with an exploration of the concept of legitimacy generally before suggesting its crucial role as the Court’s political capital. I connect the Court’s legitimacy with public perceptions of its decision making, studying the sources and effects of the so-called “myth of legality.” The discussion then turns to a case study of the John Roberts and Neil Gorsuch nominations, in which I unveil a novel methodology for evaluating the use of legitimizing and politicizing rhetoric by U.S. senators. Finally, I present the results of a survey experiment that offers new evidence that the American people are both intolerant of politicization and have remarkably durable attitudes about the Court. In all, I find that the Court remains subject to customary expectations of its legality, implying that the strategic use of politicizing rhetoric to pursue electoral gains could have deleterious effects on the Court’s legitimacy and the efficacy of the three-branch system of government.