Abstract: Justice Holmes famously observed that “[g]reat cases . . . make bad law.” The problem may be especially acute in the domain of national security, where presidents frequently interpret their own powers without judicial review and where executive precedents play a large role in subsequent interpretive debates. On the one hand, some of the historical assertions of presidential authority that stretch constitutional and statutory language the furthest seem hard to condemn in light of the practical stakes. On the other hand, to credit the authority of executive precedent risks leaving the president dangerously unbound. To address the conundrum posed by executive precedent, this Article proposes a two-tiered theory for the interpretation of presidential powers. Framed as an analogy to a position in moral philosophy known as “threshold deontology,” two-tiered interpretive theory treats rules that restrict executive power as normally inviolable, not subject to a case-by-case balancing analysis. Analogously to threshold deontology, however, two-tiered theory also recognizes that when the costs of adherence to ordinary principles grow exorbitantly high, extraordinary interpretive principles should govern instead and should result in the upholding of broad presidential power. For reasons that the Article explains, resort to extraordinary reliance on second-tier justifications for assertions of sweeping executive authority involves a legal analogue to “dirty-handed” moral conduct and should be labeled accordingly. And executive precedents set in extraordinary, second-tier cases should not apply to more ordinary ones. Through its conjunction of elements, two-tiered interpretive theory furnishes analytical and rhetorical safeguards against executive overreaching, but also allows accommodations for truly extraordinary cases.