In March 1947, France and the United Kingdom signed a Treaty of Defensive Alliance in Dunkirk in which they agreed to cooperate militarily. This alliance was widened with the signing of the Brussels Treaty in March 1948, by France, the UK, Belgium, the Netherlands, and Luxembourg. This established the Western Union which, with the signing of the October 1954 Paris Agreements, evolved into the Western European Union .
Members pledge to come to aid of one another in case of attack.
The WEU represents a more autonomous, regional approach to European security by encouraging member nations to provide for their own defense. Formed by the Washington Treaty on 4 April 1949. Common defense organization designed to prevent or repel aggression against member states. Headquartered in Brussels, Belgium. Like the WEU, NATO members pledge to come to each other's aid in case of attack.