How 27 nations share sovereignty through a unique legal order

Countries & Cities · Published 29 September 2026 · Updated 25 October 2026 Swipe more like this →

In short: The European Union is more than a simple alliance. By pooling their sovereignty, member states have created a supranational system where shared laws can actually supersede national ones. This complex web of shared authority governs everything from trade to the fine details of domestic policy.

At its core, the European Union operates on the principle of subsidiarity, meaning decisions are made collectively only when they cannot be effectively handled by individual nations. This process, known as the 'pooling of sovereignty,' allows the 27 member states to share authority through various EU institutions. While some policies require a unanimous vote in the Council, others are decided via qualified majority voting. This structure is supported by a unique legal order that, following a landmark 1964 ruling by the European Court of Justice, is considered both supreme and legally binding across all member states.

The path to membership is strictly regulated by the Copenhagen criteria. To join, a candidate must demonstrate a commitment to democratic governance, a free-market economy, and the rule of law. Furthermore, any new state must agree to adopt the 'acquis communautaire'—the massive body of existing EU law—and obtain the unanimous consent of all current members. While the union's foundations were laid in the 1950s by six core states including France, West Germany, and Italy, the bloc has expanded significantly through various enlargements over the decades.

Membership is not without its complexities or risks. While the EU lacks a formal mechanism to expel a member, Article 7 allows for the suspension of certain rights if a state persistently violates fundamental principles like democracy or human rights. Conversely, the Lisbon Treaty introduced Article 50, providing a formal procedure for withdrawal, a mechanism famously utilized by the United Kingdom, which officially left the bloc on 31 January 2020. This history of movement highlights the delicate balance between national independence and the shared obligations of the union.

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