World WarⅠ(1914-1918): issuses his proclamation of neutrality on behalf of the people of the United States. American troops played an important role in turning the tide of the war. In january 1918, Presiden Wilson proposeed his Fourteen Poinnts as the basis for peace negotiation.The Versailles Treaty was signed on June 28,1919.
World WarⅡ(1939-1945):In the early days, government adopted a sit-on-the-face policy. But American government feared that the Axis countries were winning the war and that would threaten their security and interest.In June 1944, America , British and Canadian forces landed on the beaches of Normandy. In April 1945, a comference organized the United Nations.
Korean War(1950-1953): In 1947, Prisident Truman declared the Truman Doctrine in order to establish the U.S. hegemony. In April 1949,the U.S. formed the North Atlantic Treaty Organization.
The Vietnam War(1954-1975):President Nixon reestabished the relation with China and negotiated the first Strategic Arms Limitation Treaty with Soviet Union.One of the major foreign policy goals Clinton gains in his first administration was made in November 1993.Congress approved the Norse American Free Trade Agreement.