Some constitutional theorists defend unbounded executive power to respond to emergencies or expansive discretionary powers to complete statutory directives. Against these anti-Madisonian approaches, this Article examines how the textual assignment of republican virtues helps to constitute and constrain the president’s power. The Madisonian solution for constitutional constraint both creates institutions for unenlightened statesmen and relies on virtue to make governing possible. Constitutional responsibility is a consistent textual theme found in the command to “take Care that the Laws be faithfully executed,” the responsibility to remain faithful to the office of president, and the obligation to preserve the Constitution itself. Although presidential discretion in executing and in interpreting the laws is inevitable, this Article explains why presidents are constrained by virtues such as care and fidelity, by integrity in interpretive practices, and by the normative and structural obligations of office. This Article contends that these Article II obligations, paired with the statutory and implied constitutional duty to do only what is both necessary and proper, provide textual grounds for thick normative constraints on presidential power even in the absence of more robust structural constraints. A president’s “necessary” power to complete statutory directives is constrained by obligations to do only what is “proper.” A president has great responsibility both in executing the laws and in constituting the national community through constitutional practices and commitments.