Scholarly "realism" has been the dominant approach in the study of U.S. – Mexican relations; it has portrayed the Mexican government as a unified and calculating rational actor. Nonetheless, much of the reality of U.S. – Mexican relations has never been explained well by that approach. In this work, I assess the utility of other explanations for understanding U.S. – Mexican relations in the 1980's and 1990's. In particular, I consider the contributions of approaches based on international regimes and institutions, "games" played at multiple levels, and signaling a behavior.