This dissertation examines the connection between costs of interstate war and postwar domestic politics of countries that waged them. Previous research focused primarily on explaining the chances of survival of war leaders by factors like outcome of war, culpability and regime type. This project contends that the variation in level of domestic hostility facing postwar governments also needs explanation, independent of the tenure of individual leaders. This can be operationalized by counting political events that make it harder for an incumbent to govern effectively. This is the logical basis for replacing a dichotomous dependent variable (i.e. survival versus removal of a leader) with a combined count of antigovernment activities over a finite postwar period of five years. The study hypothesizes that the higher the cost incurred by a country in a war, the greater the likelihood that it will witness manifestations of antigovernment hostility. The hypotheses were tested using cross-national data from a sample of warring countries from the period, 1919-1999. Countries that suffered civilian fatalities during war, tended to be at greater risk of overt anti-government hostility in the postwar period. As a measure of costliness, battle deaths did not work as a predictor of postwar threats faced by governments of warring states. The quantitative analysis was supplemented by case analysis of two countries - Paraguay after the Chaco War (1932-35) and Egypt after the Six Day War (1967). The Paraguayan case demonstrated how counter-elites can successfully exploit popular discontent caused by the costs of the war to discredit and depose a victorious wartime leader and his coalition. On the other hand, Egypt in the aftermath of the 1967 war illustrates that leader turnover is only one among many possible political consequences of war. A factional struggle within the pre-war winning coalition and popular expressions of antigovernment sentiment are possible without resulting in the removal of a wartime leader. Secondly, it shows why outcome has consistently been a powerful predictor of a war's domestic effects.