Reconsidering sovereignty in security and defence cooperation: The case of European ‘great powers’

The establishment of integrative commitments between states in the field of security and defence is an underexplored issue in international relations. This article is a case study of Franco-British security and defence cooperation in the Lancaster House Treaties (LHTs). France and Britain created a format for cooperation on their nuclear deterrent which involves integrative commitments. I argue that in order to account for their decision to establish such commitments, we cannot solely rely on rationalist explanations. In order understand the French and British choice of partners and the scope and depth of commitments the LHTs entails, it is necessary to incorporate an approach that places significance on parallels in states' national roles. The article contributes to the debate on international cooperation by suggesting that a comprehensive approach is necessary in order to account for integration between states in the field of security and defence.