The European Union has kept the peace in Europe, especially as between Germany and France, for 70 years since the end of the Second World War. This is untrue. It’s the other way round.
Peace in Europe has allowed the European Union to set down roots, thrive and expand. And the source of this peace? One: the Marshall Plan, which from 1948-52 pumped hundreds of billions of dollars in current prices into Europe in order to “rebuild war-devastated regions, remove trade barriers, modernize industry, make Europe prosperous again, and prevent the spread of communism” (Wikipedia). Two: NATO. It’s probably unfashionable to admit, but the American commitment to NATO protected Europe, guaranteed security and eventually led to the collapse of the Soviet empire.
The EU today is the beneficiary, not the cause, of this dispensation.