Today the leaders of both the European Union and the United States proclaim the strength of their ties and mutual support for each other's policies and values. It is certainly the case that economic relationships are deeply embedded, given the extent of trade and investment between the two economic superpowers. But conflicts arise repeatedly, sometimes leading to economic sanctions imposed as temporary surtaxes on the imports from the trading partner found guilty of violating international agreements according to the World Trade Organization (WTO). Each party feels especially aggrieved when the other does not appear to share its concern to maintain a particular policy that has been taken for granted as part of the shared heritage of the Atlantic community. Such misunderstandings and mutual exasperations date back to the origins of the European Union in the immediate aftermath of World War II. It's useful for understanding the sources of continued tension in EU–US relations to take a fresh look at the period before the creation of the European Economic Community in 1958. Over this formative period, 1945–58, both European leaders and American policy-makers laid down the foundations that set the course of development for the European Union and the individual nations that emerged from Nazi domination. On both sides of the Atlantic, key decision-makers were determined to avoid the mistakes made after the conclusion of World War I – mistakes that had led to World War II, in the opinion of most.