Contrary to most predictions and contemporary analysis, innovation with regard to strategic doctrine, military posture, and institutions has left the deep structure of the U.S.-European security bargain intact. The allocation of rights and responsibilities among the contracting parties to guarantee each others? security interests has survived the end of the Cold War. The United States continues to exercise robust leadership, and the Europeans have sustained recognition of their junior status vis-à-vis the Americans, thus making transatlantic security cooperation an instance of enduring hierarchy. This paper defends this non-conventional empirical claim, and offers a logic that explains stability at the level of deep structure.To defend the empirical claim, I do two things: First, I conceptualize the transatlantic security relationship of the Cold War era as a multi-dimensional contract, whose parties have entered into a hierarchical (authority) relationship. In contrast to (Realist) advocates of the discontinuity thesis, transatlantic security cooperation served not only to collectively defend against an external threat, but provided mechanisms that allowed the contracting parties to reassure each other of their benign intentions. In contrast to recent influential contributions in the (Liberal-institutionalist) continuity school, I emphasize that the European allies conferred special rights and privileges on the United States so that its asymmetric share of the material burden went hand in hand with an asymmetric amount of (legitimate) political discretion, yielding hierarchy. After defining the status quo baseline in this fashion, I show that the contracting parties have not decisively deviated from it either prior to or since the end of the Cold War.Existing explanations for the trajectory of U.S.-EU relations fall short in three ways: First, they do not capture the assertiveness with which the United States has pushed for a strategic reorientation of the security bargain, both prior to and after the events of 9/11. Second, they neglect to reflect on the prevailing lack of intra-European consensus with regard to security and defense policies. Finally, in ignoring the dynamics just mentioned, they sidestep the actual puzzle: Why, despite a U.S. drive for change at the operational level, and a lack of unified European loyalty to the original bargain, has the status quo prevailed? I argue that the deep structure of transatlantic security cooperation has remained stable for two reasons. First, its European partners have recognized that the bargain underlying the European Union cannot be modified so as to present a functional substitute for junior membership in the transatlantic club. In fact, the vitality of the intra-European bargain, both before and after its post-1990 amendments, is structurally dependent on the preservation of the transatlantic status quo. Second, in light of Europe?s voluntary subordination, the United States recommitted to the transatlantic alliance, since it allowed for the exercise of robust European, and by extension, global leadership without the exigencies that power projection through ad hoc coalitions of the willing impose. This project contributes both to the substantive debate on transatlantic security relations, and to theoretical discussions over the relative conceptual and explanatory validity of balancing and binding models in security studies. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]