This investigation will explore the question: To what extent did the result of Korean war impact America’s execution of containment policy? The years 1949 to 1979 will be the focus of this investigation and will analyze the increase defense budget in South Korea, North Atlantic Treaty Organization improved the relationship with other countries, the alliance among with other countries. The purpose of this investigation it will focus containment policy of America as it is against the expansion of communist.The main source will be evaluated is from Office of the Historian’s study “Containment and Cold War, 1945-1961.” The origin of this source is valuable because The Office of the Historian is provided by many professional historians who are major in the study of U.S. containment policy. The Office is managed by DR. Stephen Randolph, The Historian of the U.S. Department of State. Thus, this website is should be accurate and reliable.Section 2: InvestigationIn 1949, President Truman announced The Truman Doctrine, a policy that attempt to block the Soviet expansion during the Cold War. This doctrine inspired the most important and first containment policy – stop the spread of communism (Weebly). The idea of “containment” originally comes from U.S. diplomat to Soviet, George F. Kennan. This policy was implemented first in Greek and Turkey to block the invasion from Stalin’s regime and ambition to overtake Eastern Europe. Even though America and its allies successfully stopped Stalin’s goal for Europe, Stalin had already began to cooperate with Mao Zedong in China. After China became red, all the evidence indicated that Korea might become the next domino to fall into communist country. Eventually, America’s biggest worry occured on June 25, 1950 – the beginning of Korean War. North Korean troops gained majority of victory at first. Then, America dominated the situation later. The signing of Armistice Agreement of 38 degree parallel line marked the end of this war (Hickey, 2011). The consequences of Korean War motivated American to become more aggressive on its execution of containment policy during Cold War.Soon after Korean War, American government immediately passed the law to increase its defense budget in Korea. American leaders and officials believed that the best defense to respond to the Soviet threat was to massively build up their military.” President Truman, already under fire from a growing Republican contingent in Congress for being “soft on Communism,” was determined to prevent the Communists from seizing South Korea. Truman ordered naval and air support for South Korea (Trowbridge 556).” Seeing China fell into Communism, American public was fearing that Communism would soon become the dominator of the world and became a press toward Truman to have harsh strategies against or contain the expansion of communism.A Strong push for North Atlantic Treaty Organization (NATO) helped American to build up and improved the international relationship with other countries, especially Eastern European countries under Soviet control. NATO established as a defensive military alliance originated in 1949 by the US and 11 of its Western European allies. It was created as an alliance against the threat of communism, the Soviet Union. In 1954, the Soviet Union suggested that it should join NATO to preserve peace in Europe, but the NATO countries worrying that the Soviet Union motive was to weaken the alliance (Stephen). The United States realized that Europe was vital to the prevention of communist expansion across the continent. Consequently, Secretary of State George Marshall proposed European Recovery program as an economic aid to Europe, not only improved European economic but also promoted the idea of shared interests and cooperation between the United States and Europe. The alliance among with other countries was also an important factor for America to keep maintaining containment policy. American alliance with Indochina in 1953 including Defense treaty US and Taiwan; ANZUS Pact among America, New Zealand, and Australia; US military alliance with Philippines. First, the United States tries to disrupt and weaken China’s communist government because they believed that China was very aggressive on threatening its noncommunist neighbors. Hence, the U.S. Congress passed the Taiwan Relation Act (TRA) on March 28 and 29, 1979 (Richard, 2004). The TRA not only securing Taiwan’s security but also contributed a lot to the West Pacific’s peace and stability. Second, pacific security treaty was signed in 1951, it was a treaty between Australia, New Zealand, and the United State(New york time, 1985). The purpose of this security treaty was to support each other in any event of aggression and settle disputes by using peaceful means.The United States offered the pact because they want to maintain the relationship between the three nations, so they could ensure their collective security in the Pacific region. Lastly, in the early years of the cold war, based on a defense treaty between Washington and Manila, they conduct joint exercises and other military training to improve the preparedness of the armed forces of the Philippines in response to prevent any conflict in Pacific region (Eleanor, 2016). Consequently, the relationship is also considered to be a major pillar of the U.S. strategic rebalance to Asia. Additionally, the alliance with the Philippines allowed the United States to better promote stability and peace in an increasingly volatile area.After the result of Korean War, American realized that they should become more aggressive on its execution of containment policy since they couldn’t bear any countries that are going to falling to be a part of communist. In order to keep maintaining its execution of containment policy, American government passed the law to increase its defense budget right after Korean War. Furthermore, North Atlantic Treaty Organization was established to improve the relationship with Eastern European countries and defend the threat of communist. Finally, the alliance with other countries have played an important role in Asia, this collective defence ensured the security in Pacific region. In the result of Korean War, the United States play the character of “global policemen” for its containment policy.