Abstract. 

Modern UN peace operations frequently deploy in non-international armed conflicts (NIACs). Their activities tend to support governmental forces in stabilizing the country, including the combat against non-state actors. This is one of the most prominent examples of ‘support relationships’ or ‘partnered warfare’, namely situations in which a foreign partner provides military support for an ally in an armed conflict. This also raises the question, however, of the legal status of UN peace operations and their activities in such circumstances. This article examines the legal situation and finds that the current legal tenets regarding UN peace operations becoming a party to a conflict and individual peacekeepers directly participating in hostilities do not address the issue in a satisfactory manner. It also finds that while the International Committee of the Red Cross has proposed the support-based approach to clarify the issue, this lacks an appropriate legal basis. The article argues that a ‘totality-of-the-circumstances’ approach regarding the existence of a NIAC, which corresponds to the original spirit of Common Article 3 of the Geneva Conventions, provides a proper legal basis which addresses identified concerns. The article concludes by discussing such an approach’s advantages and drawbacks in the case of support relationships.