1. Truman Doctrine
The Truman Doctrine was the Doctrine imposed by then President of the United States Harry S. Truman. The Truman Doctrine laid out the U.S.'s plan of containment, or setting up spheres of influence to contain the spread of Communism. This would include providing funds, material, soldiers, and supporting any existing governments that are anti-communist, or anti-communist forces that are operating in the area.
The Cause of the Truman Doctrine is the expansion of influence of Communism.
The Effect is the U.S. providing security, funds, and military help too any anti-communist groups in foreign countries.
2. Marshall Plan
The Marshall Plan was the U.S's plan in providing trillions of dollars to existing pro-democracy states (generally in Europe) to help them rebuild their infrastructure, government, military, and economy.
The Cause of the Marshall Plan was World War II, and rebuilding Europe, as well as containing the spread of Communism.
The Effect is the rebuilding of Europe as well as making Europe pro-American and allowing Europe to enter into the American sphere of influence.
3. Berlin Airlift
The Berlin Airlift occurred 1948-1949, when the U.S.S.R closed off all transportation in-between western Germany and the western half of Berlin. They created the Berlin Wall and tried to force the Democratic nations to give up on, first the capitol of Germany, and then all of Germany. However, the Berlin Airlift was created to supply German citizens in western-berlin throughout the blockade, and even sent christmas presents during Christmas. The U.S.S.R, seeing the Western countries's resolve, lifted the blockade shortly after.
The Cause of the Berlin Airlift is the Berlin blockade imposed by the U.S.S.R.
The Effect is the lifting of the blockade and the weakening of the U.S.S.R's influence in Germany.
4. Korean War
The Korean War was a war from 1950-1953, where the U.S. and N.A.T.O was able to successfully contain the expansion of Communism in Korea. After World War II, Japan's island colony Korea was taken away from them, and to appease both the U.S.S.R & U.S, was split into two nations, North Korea being under U.S.S.R's control, while the U.S. influenced South Korea. North Korea struck first in an effort to control all of Korea and place it under Communist rule, but with the help of U.S. & N.A.T.O, South Korea was able to fight back and continued to stay as a country.
The Cause of the Korean War is the splitting of Korea into two parts, each with it's own sphere of influence. Communism wanted to influence all of Korea, and so started the war.
The Effect is the successful containment of Communism, and the continuation of the two state solution.