The European Union began life in 1951 as the European Coal and Steel Community — six countries pooling control over the raw materials of war, on the theory, voiced by Robert Schuman and Jean Monnet, that two world wars had been quite enough and that integration should make a Franco-German war "not merely unthinkable, but materially impossible." Seventy-five years later, twenty-seven countries share a single currency (most of them), no internal borders (most of them), a parliament that drafts binding regulation, a court whose rulings override national law, and a single market of 450 million people that is the world's largest consumer economy and a global regulatory standard-setter. There is no historical precedent for the depth of voluntary integration the EU has achieved.
The European project has always been politically thin and economically thick — long on regulatory harmonization, short on cultural common identity, with no demos to match its institutions. Integration deepened in stages: the 1957 Treaty of Rome built a common market, the 1992 Maastricht Treaty created the EU proper and committed it to a single currency, and the euro entered circulation in 2002. It expanded eastward after 1989 to embrace the formerly Communist states, growing from twelve to twenty-eight members between 1995 and 2013, an enlargement that doubled its membership while leaving its decision rules largely intact. It weathered the 2010 sovereign-debt crisis — barely, with severe damage to Greece, where bailout conditions cut output by a quarter and exposed the flaw of a monetary union without a fiscal union to match it. It lost the United Kingdom in 2020, Brexit being the first reversal in its expansionary trajectory; and it is now confronting the question of whether to admit Ukraine in some form, and what to do about Russia on its eastern frontier. The persistent internal argument is between deepeners (those who want stronger central institutions, fiscal transfers, joint debt, an EU army) and broadeners (those who want more members but fewer common policies) — a tension structurally hard to resolve, because every enlargement makes consensus among more vetoes harder, and every deepening demands sovereignty that member states guard jealously. Brexit gave the deepeners ammunition; the post-2022 security shock accelerated forms of integration stuck for decades — the first jointly issued EU debt (NextGenerationEU), coordinated arms procurement, energy decoupling from Russia.
The EU is currently the world's largest experiment in post-national governance, and it is being stress-tested by Russian aggression on its border, by American retrenchment under a second Trump administration that questions NATO's guarantee, by demographic decline and an aging workforce, and by economic competition from both the US and China that has left it with no homegrown tech giant. Whether it consolidates into a real geopolitical actor or fragments back into a free-trade zone — pulled apart by nationalist movements from Hungary to France — is one of the most important questions in the architecture of the next decade.