In recent years, a new creature has emerged on the institutional landscape: The Schmitelsen Court. This court is the end-product of a combination of the positions presented by Hans Kelsen and Carl Schmitt in their famous debate over the institutional identity of the guardian of the constitution during the Weimar years. The Schmitelsen guardian is a court thus fulfilling Kelsen’s vision of the constitutional court as the guardian of the constitution. Nevertheless, it possesses the mission, the means to achieve it, and the source of legitimacy that Schmitt envisioned for the president as the guardian of the constitution. In this Article, I focus on the Schmitelsen Court’s source of legitimacy that differs greatly from the traditional source of judicial legitimacy that Kelsen envisioned for the guardian. Whereas Kelsen viewed legal expertise as the guardian’s source of legitimacy, Schmitt viewed public support as filling this role. After analyzing these two positions, I explain why it is vital for the Schmitelsen Court to harness public support as its source of legitimacy. I proceed by examining how the Schmitelsen Court model manifests itself in three case studies. In the US, Alexander Hamilton—in The Federalist No. 78—raised the notion of the guardian of the constitution long before Schmitt and Kelsen. He designated the judiciary as the guardian and ascribed its source of legitimacy to expertise. After describing how in recent decades the US Supreme Court adopted the Schmitelsen understanding of judicial legitimacy, I turn to examine the Israeli Supreme Court and the European Court of Human Rights. The relevance of these latter two courts stems not only from their adoption of the Schmitelsen Court’s understanding of judicial legitimacy, but also from the strong influence of the Weimar lessons on their evolution into Schmitelsen guardians.