The current national security policy of the United States makes it likely that increased numbers of American armed forces will be engaged abroad in coming years. They will carry out a range of missions from war fighting to peace enforcement and peacekeeping operations – now referred to as “stability operations” by the Pentagon. They may also more often take on the role of an occupation force. In peace enforcement, peacekeeping and as an occupation authority in particular, military contingents have important resources that they may, should doctrine allow, employ in support of peacebuilding. They may also, by virtue of their command of such resources, have an unwitting, negative impact on important social, economic and political transitions and the consolidation of peace. Done well, the military’s support in peacebuilding may accelerate progress toward security goals. Conversely, a lack of sensitivity in stability operations may undermine a fragile peace and weaken local capacities to manage conflict. The example of the changing character of peace operations in Bosnia illustrates several important considerations for U.S. military forces in war to peace transitions.