Nearly 25,000 private security contractors are estimated to operate currently in Iraq. Many earn between $100,000 and $200,000 per year – up to ten times more than they were paid in the national armed or police forces where most of them received their training and worked for many years. Unsurprisingly, military personnel are leaving the armed forces in large numbers. This paper examines the emergence of the private military contractor in North America and Europe as a new model of the soldier. It proposes that there have been three ideal-type models of the soldier since the beginning of the 20th century: the citizen-soldier, the military professional and the military entrepreneur. Each of these models is based on distinct notions of the relationship between the citizen, the soldier and the state. In particular, these types of soldiers can be distinguished in terms of their ideal relation with the state, their motivation, their identity, and their connection between political and military roles. Following a detailed analysis of the three models, the second part of the paper proceeds to investigate how the shift from the citizen-soldier to the military entrepreneur can be explained. It suggests that arguments which focus on the changing national and international security environment are incomplete. While the security environment does play a role, its impact is filtered by the changing balance between the ideological principles which underlie the different models of the soldier in the transatlantic region, namely between republicanism and liberalism. ..PAT.-Conference Proceeding [ABSTRACT FROM AUTHOR]