First used in a speech before he assumed the presidency, Theodore Roosevelt's Big Stick diplomacy was his belief that intelligent forethought must be coupled with military muscle.

The so called “Truman Doctrine” argued that it was the responsibility of the post-war United States to support the extension or maintenance of freedom, personal liberty and democratic ideals throughout the world. The quote comes from a speech given by Truman, to Congress, when he was calling for funds to support those people in Turkey and Greece who favored democracy. 

The Nye Report was a Senate report issued during World War One that stated that American banks and corporations had tricked the American people into supporting a war so that they could gain profit from the sale of arms, post-war reconstruction projects and the elimination of foreign competitors. The report was widely quoted as a very significant reason for avoiding conflict in Europe and Asia in the 1930s and persisted into the early 1940s, as a reason not to join World War Two on the side of the allied forces

The correct answer is Grover Cleveland. Taft, Roosevelt and McKinley all initiated conflicts or invasions that advanced American interests abroad. All three believed that the United States needed to expand its influence around the world to serve national interests. Wilson, who was staunchly against European Imperialism and ideologically opposed to America’s interference in foreign nations, still managed to send American troops into Nicaragua in 1914 to occupy the country and Haiti and the Dominican Republic in the years immediately after. Thus, Wilson can be seen as an Imperialist in practice if not in ideology. Grover Cleveland, on the other hand, came to the Presidency in the years shortly before Imperialist ideology took over the office, and once out of office he was a devoted member of the American Anti-Imperialist League. The Anti-Imperialist League believed that Imperialism violated the republican principles that America had been founded on, and they fiercely objected to any forced occupation of foreign lands. 

Woodrow Wilson explained America’s participation in World War One as an intervention of necessity. Peace and stability needed to be provided for in Europe and the world. Many of his fourteen points dealt with the maintenance of territories or the creation of new nation-states. However, he did not argue for the dismantling of the Austro-Hungarian Empire, instead he wished to incorporate them into a peaceful post-war world. In addition, he demanded a reduction of army size and strength and the removal of barriers to free trade and navigation of the seas. Finally, he called for the creation of a League of Nations, to co-operate on the maintenance of peace and prosperity. The fourteen points were generally viewed positively by European people, but negatively by European heads of state. 

The Boxer Rebellion took place in China at the turn of the twentieth century. Chinese nationalist forces had long held grievances against the spheres of influence held by various European nations, and the United States, in Chinese territory. The rebellion was largely fought to remove the influence of foreign powers from China and to dispel Christian missionaries who were attempting to convert the population. The Rebellion ended in defeat for the Boxers and an increase in protected trading rights for the Imperial powers in Chinese territory. 

The America First Committee was set up in 1939 and 1940 in order to prevent the United States from becoming embroiled in the “European war.” The committee argued that President Roosevelt was deceiving the American people with promises of neutrality. They argued that Roosevelt was aiding the Allied powers and drawing America closer and closer to conflict with Germany. The America First Committee reflected the general mood of the American public in 1939—the vast majority of whom wished to avoid conflict; however, with the Pearl Harbor attacks in 1941, the America First Committee rapidly disbanded and American public opinion reversed. 

The foreign policy initiatives enacted during the Presidency of William Taft are generally referred to under the phrase “Dollar Diplomacy.” Taft believed that, in order to advance America’s economic and diplomatic interests and encourage global stability, the United States should encourage private American investment in foreign nations.

Vietnam had been a French colony until World War II, when it was invaded by Japan.  After the war, the country was split into two nations, the Communist (and Soviet backed) North Vietnam, and the Democratic (and Western backed) South Vietnam. While America had always backed South Vietnam in the ongoing conflict between the two, in 1964, the U.S. officially declared War against North Vietnam after the Gulf of Tonkin incident. The reason given for this involvement from President Lyndon Johnson and hawks in Congress was that the spread of communism had to be stopped, and that Vietnam was crucial to this effort.

Most associated with the presidencies of Truman, Kennedy, and Johnson, containment was an attempt to stop the spread of Communism to countries where it was not currently the form of government.  The other policies advocated at the time were rollback, attempting to actually reverse new communist government victories, and appeasement, which sought to make concessions with Communist governments to avoid all out conflict.