For decades, the United Kingdom has had an ambivalent and sometimes contentious relationship with the European Union. London has kept its distance from Brussels’ authority by negotiating opt-outs from some of the EU’s central policies, including the common euro currency and the border-free Schengen area. Even still, the EU’s faltering response to recent crises has fueled a renewed euroskepticism. Advocates for a British exit, or Brexit, from the union argued that by reclaiming its national sovereignty, the UK would be better able  to manage immigration, free itself from onerous regulations, and spark more dynamic growth.

After the victory of the Leave campaign in a June 2016 referendum on the UK’s future in the bloc, the risks of separating from the EU became clearer. With financial markets in tumult and the resignation of Prime Minister David Cameron, the UK now faces the possibility of losing preferential access to its largest trading partner, the disruption of its large financial sector, a protracted period of political uncertainty, and the breakup of the UK itself. Meanwhile, Brexit could accelerate nationalist movements across the continent, from Scotland to Hungary, with unpredictable consequences for the European project.

What is the history of the UK’s membership in the EU?

The UK remained aloof from the continent’s first postwar efforts toward integration, the European Coal and Steel Community (ECSC) and the the European Economic Community (EEC), formed in the hopes of avoiding another devastating war. “We did not enter the EU with the same political imperatives [as France and Germany],” Robin Niblett, head of the London-based think tank Chatham House, has argued. “We had not been invaded, we did not lose the war, and we have historical connections to all sorts of other parts of the world from our empire and commonwealth.”

The UK didn’t join the EEC until 1973. The British people approved membership in a 1975 referendum, but suspicion of political union with the rest of Europe remained strong. Critics argued that the European project was already moving beyond mere economic integration and toward a European “superstate.”

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