While the literature on the political use of military force by the USA has undergone tremendous growth in recent years, one crucial feature of this foreign policy activity has not been modeled - the conditions that give rise to the crises that precipitate a use of force. It is possible that many of the findings on the diversionary use of force obtain because of problems with selection effects. More uses of force may occur during certain periods simply because more crises occur during these times. Therefore, I explain how we may model crisis occurrence and the use of force to help us better understand the role of selection effects and the salience of domestic conditions in the decision to use force. I outline several hypotheses regarding the influence of domestic and crisis-specific factors to predict when opportunities to use force will occur and, given some opportunity, when a president will use military force. The results demonstrate that by not accounting for selection effects in the decision to use force by US presidents, we may have erroneously concluded that presidents use force to divert public attention.