The commercialisation of military services has increased in importance since the end of the Cold War. Commercial Military Service Providers (CMSPs) have found increased respectability and worked in states on every continent. Writing on CMSPs has similarly increased. Several high profile incidents have come under intense scrutiny, and has led to some portions of the literature demonising their use. However, there are still conceptual and theoretical issues which have been under explored. This thesis contributes to the literature which has sought to address this theoretical lacuna. Historical Sociology and comparative analysis are employed to analyse the implications of CMSP use on the state. A modified version of the Ideological, Economic, Military and Political (IEMP) model developed by Michael Mann, is used to theorise the impact of commercial security providers on existing sources of power within the state, and the relationship between them. The thesis uses two case studies which are representative of the use of CMSPs during this time period. The Sierra Leone Civil War and the invasion and reconstruction of Iraq since 2003. It will be argued that CMSPs alter the balance between power structures within the state, positively and negatively affecting the power of the state. The short term use of CMSPs has proven to be useful and of increasing importance; especially when military weakness is an urgent problem. However, although there has been no example of CMSPs intentionally threatening state stability, they can also subvert the power of the state. CMSPs, particularly when used for an extended period, have undermined the relationship between the sources of power, undermining political stability. Most significantly they weakened the state by undermining the strength it gains from its embeddedness in society.

Employant des salariés pour exécuter les missions de sécurité et de défense que peuvent leur confier des Etats, des organisations internationales ou des entités non étatiques. Cette forme particulière de production de la sécurité n’est pas entièrement appréhendée par les conventions internationales et les législations internes des Etats. De cela résulte une absence de statut juridique international de ces acteurs qui sont de plus en plus présents dans la gestion des conflits armés et dans les opérations de maintien de l’ordre. Les obligations particulières de leurs clients ne sont pas non plus déterminées. Ce défaut d’encadrement spécifique avéré ne signifie pas qu’il y ait un vide juridique dans ce secteur d’activité. Certaines règles internationales et les droits nationaux peuvent effectivement s’appliquer aux activités des SMSP et aux contractants de ces dernières. Seulement, l’efficacité que devaient avoir de telles normes face à des situations qui n’ont pas été prises en compte lors de leurs adoptions, ne saurait être acquise. D’où un processus de régulation internationale et de règlementation nationale initié depuis quelques années par les Etats mais aussi par les organisations internationales. Les sociétés elles mêmes se sont senties concernées par la production de règles encadrant leurs activités et se sont lancées dans la mise en place de code conduite. L’imperfection guette toutes ces nouvelles règles spécifiques destinées à corriger les lacunes des conventions internationales et des lois internes. Ce qui nécessite la proposition de solutions envisageables dans le but de mieux prendre en compte les intérêts des SMSP et la protection de ceux qui s’exposent aux risques que procurent les prestations privées de sécurité militaire. / Private military and security companies are legal persons of private law with employees to perform security missions and defense that can give them some states, international organizations or non-state entities. This particular form of production safety is not fully understood by international conventions and domestic laws States. Result of this lack of legal status of these international actors is increasingly involved in the management of conflicts and peacekeeping operations order. Specific obligations of their clients are not determined. This lack of specific guidance proved does not mean that there is a legal vacuum in this sector. Certain international standards and national laws may actually apply to the activities of PMSCs and contractors thereof. Only efficiency that would have such standards in situations that have not been taken into account when adopting them cannot be acquired. Hence a process of international regulation and national regulation initiated in recent years by states but also by international organizations. The companies themselves have felt involved in the production of rules governing their activities and have engaged in the implementation of code of conduct. The imperfection watching all these new rules designed to correct specific deficiencies in international conventions and laws. This requires the proposal of possible solutions in order to better take into account the interests of PMSCs and the protection of those who are exposed to risks that provide private benefits of military security.