Jurisdictional error has a prominent role in entrenched review of executive action in Australia, despite near universal acknowledgment that it does not illuminate the operative norms of administrative law. A statutory approach to jurisdictional error dominates in Australia, despite widespread agreement that the concept is merely conclusory. It is widely assumed that the path to explain - or to challenge - these matters is through better understanding a legislative supremacy rationale for jurisdictional error. However, a more compelling account of jurisdictional error can be drawn from a fundamental constitutional characteristic of executive power: The lack of inherent executive power over legal rights or obligations. By drawing out this distinct constitutional foundation for review of purported executive decisions, this article shows that the prominence of jurisdictional error in entrenched review of executive powers is explicable for substantive constitutional reasons, which reasons also cast light on why the concept does not require a statutory approach to the grounds of entrenched review.