Germany attacked France three times in three generations from 1870, losing 1 – 2; without the EU might Germany have tried to square the series? England and France battled each other repeatedly between the 14th and 19th centuries but never in the last 200 years. Sometimes history doesn’t repeat itself, we move on.
Social mobility, business connections and improved communications have reduced to negligible levels the possibility of European nations coming to blows again. There is too much commerce at stake and no competing empires.
It may have inspired its founders but the EU is no longer “a major project for peace” in Europe (Juncker, Daily Telegraph 5 March 2016). Its focus soon shifted to “more Europe” with debatable results, perhaps because the fault line lay outside EU borders where it was more capably handled by NATO.