We study a dynamic model in which a politician (most commonly an executive) makes authority claims that are subject to a hard constraint (administered, typically, by a court). At any period, the court is free to rule against the executive and thereby permanently halt her efforts to acquire more power. Because it appropriately cares about the executive's ability to address real-world disruptions, however, the court is always willing to affirm more authority. Neither robust electoral competition nor alternative characterizations of judicial decision-making fundamentally alters this state of affairs. Moreover, we show modest authority claims in one period yield opportunities for more substantial claims in the next. The result is an often persistent accumulation of executive authority and a degradation of judicial checks on presidential power.