In this paper a set of hypotheses about the conditions under which territorial disputes evolve into enduring rivalries are tested against a dataset of 129 territorial disputes in the international system from 1950-1990. During this period only 36 territorial disputes developed into enduring rivalries. The central theoretical question I address is what conditions cause foreign policy leaders to adopt non-violent and more flexible diplomatic policies over disputed territory and, conversely, when will leaders pursue territorial claims in a more aggressive and confrontational manner? To answer this question I utilize a modified realist approach which posits that foreign policy choices are shaped by the domestic political goal of state leaders to retain their position of political power. From this theoretical approach a series of hypotheses focusing on the issues at stake in control of disputed territory, the domestic political context, and the international political-military environment of challenger states are formulated. Empirical results, based on statistical tests, are then presented and provide considerable evidence of the interplay of domestic and international level variables in the decisions of state leaders whether to pursue territorial goals by means of diplomatic and military pressure over an extended period of time.