The founders of the EU had witnessed the damage caused by the inwardness and protectionism of the interwar years. They understood that sustaining economic growth was vital to drain support for divisive nationalism, and the best way to achieve this was through open markets. Though the last decade has been difficult, over the long sweep of post-war history their vision has been proved right.
Since 1960 cumulative growth in GDP per capita has been one-third higher in the EU15 than in the United States. Private wealth, which had been twice wiped out by the wars of the twentieth century, has also doubled as a percentage of national income. This was of course partly driven by the natural catching-up process after the Second World War.