Abstract

The European Union (EU) cannot be understood without reference to its institutions. But scholars differ on the questions of what precisely EU institutions are, what they do, and why they matter. This chapter defines EU institutions as decision-making bodies. It refers to the notion of EU institutional politics as the sphere of informal and formal rules, norms, procedures, and practices that shape such decision-making. The chapter explores how different theoretical traditions—international relations, integration theory, new institutionalism, the separation of powers, governance, public policy and administration approaches, and critical perspectives—think about EU institutions. Drawing on these traditions, this chapter encourages readers to think about EU institutions along five dimensions: intergovernmental versus supranational, international versus transnational, separated versus fused power, leaders versus followers, and contested versus legitimate. Seeing how the Union’s decision-making bodies move within and between these dimensions offers a deeper understanding of why EU institutions matter.