This chapter examines how international courts have applied principles of state responsibility in the context of situations of shared responsibility between multiple parties, concluding that when this occurs international adjudication becomes less suited as a process for implementing such responsibility. Substantive law of international responsibility is slowly adjusting to its increasingly relational nature, but the procedures of international adjudication in many respects are not well suited for incorporating this relational nature. There are considerable differences between states, in terms of their willingness to submit themselves to adjudication of shared responsibility claims, even within “the west,” as a result of which responsibility will often will be shared between some states, but not all. The role of international adjudication in relation to shared responsibility differs widely – both between international courts and between states – in terms of the willingness of states to subject themselves, or make use of, international adjudication. An interesting example is the adjudication of claims related to extraordinary rendition. Whereas European states, like Macedonia and Poland, were found responsible by the European Court of Human Rights in relation to their (shared) responsibility, the USA has always resisted attempts to be subjected to adjudication for their leading role in extraordinary rendition.