Intergovernmentalism and supranationalism differ in that the former is the cooperation between governments, and the latter describes action above the government level, acting with greater authority than any single member state. The EU, as a union of 28 different governments, contains some intergovernmental elements throughout the EU’s various institutions. However, some EU institutions, like the CJEU, are entirely independent from the national governments and yet exercise authority over them, making them supranational.
The intergovernmental elements of the EU are most obviously illustrated by the European Council and the Council of Ministers, both of which draw their membership from national governments. The European Council’s participants are all heads of state and direct the overall direction of the policy making process, making the European Council one of the most senior institutions within the EU and, more importantly, an intergovernmental one. Though it lacks a fixed membership, the Council of Ministers is comprised of national ministers on a range of issues (or equivalent) who sit when their respective sector is under discussion. Similarly to the European Council, the influential nature of the Council of Ministers and the participants’ origins in a national ministerial role makes the CoM a senior and intergovernmental branch of the EU.
Contrastingly, the CJEU and (to a lesser extent) the European Commission are both examples of supranationalist elements within the EU. The CJEU is the overarching institution which houses the European General Court and the European Court of Justice, both of which are independent from any national government but can act above national courts. The European Court of Justice is the highest court of appeal amongst the member states and can overturn verdicts of any national court, making the CJEU a supranationalist EU institution. The Commission lacks such a direct and substantial power, but still carries out a legislative role whilst being independent from national governments. Though there are a number of checks in place to limit the power of the Commission and keep them subordinate to the European Parliament, they still exercise a measure of influence. As the drafters of legislation, the Commission can influence specific details of some laws and, when permitted by the European Parliament, can pass delegated legislation that amends existing, non-essential EU laws. In this sense the Commission is not as obviously a supranationalist force within the EU as the CJEU, however both act as clear evidence of the supranational capabilities of the EU despite existing within a largely intergovernmentalist system.