The theory of union-government interaction presented in Chapter 2 focuses on the effect of partisan loyalties, leadership competition, and union competition on the relationships among governments, union leaders, and labor constituencies. Partisan loyalty influences the relationship between union leaders and government officials. Leadership competition, however, can interact with partisan loyalty by making leaders more aware of their constituencies to avoid replacement by rival union leaders. Union competition, in turn, affects the strategies of union leaders by shaping their relationship with other labor organizations when competing for constituencies and subsequently their bargaining power vis-à-vis governments. Chapter 3 shows the original influence of these variables at the onset of the alliance between labor unions and populist labor parties. Chapters 4 to 6 test their explanatory power in three different countries, five different economic sectors, and two different types of labor organizations (multisectoral confederations and industry-specific unions). This chapter brings together all the pieces of the puzzle in a cross-national comparison of all the case studies in Argentina, Mexico, and Venezuela. At the same time, it makes an explicit comparison of the explanatory power of different theories to account for the variation observed in the case studies.