In 1949 twelve Western nations signed the North Atlantic Treaty, a defense pact designed in large part to address the growing expansionist threat of the Soviet Union and its satellite states in Eastern Europe; the United States ratified the treaty in July of that year. The essence of the treaty was that “the Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all.” The treaty created the North Atlantic Treaty Organization (NATO), headquartered in Brussels, Belgium.