This Chapter develops an explanatory framework which organises approaches to deference in international adjudication according to how each approach structures the relationship between international and domestic decision-making authority. Section A introduces the range of domestic decisions referred to by adjudicators. It examines how adjudicators confront domestic judicial decisions, domestic decisions on domestic law, and domestic policy decisions in international private property claims. Section B organises the results of this analysis, identifying seven different ‘modes’ of deference. These range from the treatment of domestic decisions as controlling on international adjudicators (‘conclusive domestic authority’), to rejections of deference to domestic decisions entirely (‘conclusive international authority’). Between these two extremes, deference to domestic decisions also at times resulted in a suspension of the exercise of international decision-making authority (‘suspensive domestic authority’), or in a more concurrent operation of domestic and international authority (‘concurrent authority’). These distinct approaches are explored in more detail in Chapters 5 to 7.