Harry S. Truman in the context of "Marshall Plan"

Japan was occupied and administered by the Allies of World War II from the surrender of the Empire of Japan on September 2, 1945, at the war's end until the Treaty of San Francisco took effect on April 28, 1952. The occupation, led by the American military with support from the British Commonwealth and under the supervision of the Far Eastern Commission, involved a total of nearly one million Allied soldiers. The occupation was overseen by the US General Douglas MacArthur, who was appointed Supreme Commander for the Allied Powers by the US president Harry S. Truman; MacArthur was succeeded as supreme commander by General Matthew Ridgway in 1951. Unlike in the occupations of Germany and Austria, the Soviet Union had little to no influence in Japan, declining to participate because it did not want to place Soviet troops under MacArthur's direct command.

This foreign presence marks the only time in the history of Japan that it has been occupied by a foreign power. However, unlike in Germany, the Allies never assumed direct control over Japan's civil administration. In the immediate aftermath of Japan's military surrender, the country's government continued to formally operate under the provisions of the Meiji Constitution.

The surrender of the Empire of Japan in World War II was announced by Emperor Hirohito on 15 August and formally signed on 2 September 1945, ending the war. By the end of July 1945, the Imperial Japanese Navy (IJN) was incapable of conducting major operations and an Allied invasion of Japan was imminent. Together with the United Kingdom and China, the United States called for the unconditional surrender of Japan in the Potsdam Declaration on 26 July 1945—the alternative being "prompt and utter destruction". While publicly stating their intent to fight on to the bitter end, Japan's leaders (the Supreme Council for the Direction of the War, also known as the "Big Six") were privately making entreaties to the publicly neutral Soviet Union to mediate peace on terms more favorable to the Japanese. While maintaining a sufficient level of diplomatic engagement with the Japanese to give them the impression they might be willing to mediate, the Soviets were covertly preparing to attack Japanese forces in Manchuria and Korea (in addition to South Sakhalin and the Kuril Islands) in fulfillment of promises they had secretly made to the US and the UK at the Tehran and Yalta Conferences.

On 6 August 1945, at 8:15 am local time, the United States detonated an atomic bomb over the Japanese city of Hiroshima. Sixteen hours later, American president Harry S. Truman called again for Japan's surrender, warning them to "expect a rain of ruin from the air, the like of which has never been seen on this earth." Late on 8 August 1945, in accordance with the Yalta agreements, but in violation of the Soviet–Japanese Neutrality Pact, the Soviet Union declared war on Japan, and soon after midnight on 9 August 1945, the Soviet Union invaded the Japanese puppet state of Manchukuo. Hours later, the U.S. dropped a second atomic bomb on the Japanese city of Nagasaki.

The National Security Agency (NSA) is an intelligence agency of the United States Department of Defense, under the authority of the director of national intelligence (DNI). The NSA is responsible for global monitoring, collection, and processing of information and data for global intelligence and counterintelligence purposes, specializing in a discipline known as signals intelligence (SIGINT). The NSA is also tasked with the protection of U.S. communications networks and information systems. The NSA relies on a variety of measures to accomplish its mission, the majority of which are clandestine. The NSA has roughly 32,000 employees.

Originating as a unit to decipher coded communications in World War II, it was officially formed as the NSA by President Harry S. Truman in 1952. Between then and the end of the Cold War, it became the largest of the U.S. intelligence organizations in terms of personnel and budget. Still, information available as of 2013 indicates that the Central Intelligence Agency (CIA) pulled ahead in this regard, with a budget of $14.7 billion. The NSA currently conducts worldwide mass data collection and has been known to physically bug electronic systems as one method to this end. The NSA is also alleged to have been behind such attack software as Stuxnet, which severely damaged Iran's nuclear program. The NSA, alongside the CIA, maintains a physical presence in many countries across the globe; the CIA/NSA joint Special Collection Service (a highly classified intelligence team) inserts eavesdropping devices in high-value targets (such as presidential palaces or embassies). SCS collection tactics allegedly encompass "close surveillance, burglary, wiretapping, [and] breaking".

Anna Eleanor Roosevelt (/ˈɛlɪnɔːr ˈroʊzəvɛlt/ EL-in-or ROH-zə-velt; October 11, 1884 – November 7, 1962) was an American political figure, diplomat, and activist. She was the longest-serving first lady of the United States, during her husband Franklin D. Roosevelt's four terms as president from 1933 to 1945. Through her travels, public engagement, and advocacy, she largely redefined the role. Widowed in 1945, she served as a United States delegate to the United Nations General Assembly from 1945 to 1952, and took a leading role in designing the text and gaining international support for the Universal Declaration of Human Rights. In 1948, she was given a standing ovation by the assembly upon their adoption of the declaration. President Harry S. Truman called her the "First Lady of the World" in tribute to her human rights achievements.

Roosevelt was a member of the prominent and wealthy Roosevelt and Livingston families and a niece of President Theodore Roosevelt. She had an unhappy childhood, having suffered the deaths of both parents and one of her brothers at a young age. At 15, she attended Allenswood Boarding Academy in London and was deeply influenced by its founder and director Marie Souvestre. Returning to the U.S., she married her fifth cousin once removed, Franklin Delano Roosevelt, in 1905. Between 1906 and 1916 she gave birth to six children, one of whom died in infancy. The Roosevelts' marriage became complicated after Eleanor discovered her husband's affair with her social secretary, Lucy Mercer, in 1918. Due to mediation by her mother-in-law, Sara, the liaison was ended officially. After that, both partners started to keep independent agendas, and Eleanor joined the Women's Trade Union League and became active in the New York state Democratic Party. Roosevelt helped persuade her husband to stay in politics after he was stricken with a paralytic illness in 1921. Following Franklin's election as governor of New York in 1928, and throughout the remainder of Franklin's political career, Roosevelt regularly made public appearances on his behalf; and as first lady, while her husband served as president, she greatly influenced the present scope and future of the role.

The civil rights movement was a social movement in the United States from 1954 to 1968 which aimed to abolish legalized racial segregation, discrimination, and disenfranchisement in the country, which most commonly affected African Americans. The movement had origins in the Reconstruction era in the late 19th century, and modern roots in the 1940s. After years of nonviolent protests and civil disobedience campaigns, the civil rights movement achieved many of its legislative goals in the 1960s, during which it secured new protections in federal law for the civil rights of all Americans, including the Civil Rights Act of 1964 and the Voting Rights Act of 1965.

Following the American Civil War (1861–1865), the three Reconstruction Amendments to the U.S. Constitution abolished slavery and granted citizenship to all African Americans, the majority of whom had recently been enslaved in the southern states. During Reconstruction, African-American men in the South voted and held political office, but after 1877 they were increasingly deprived of civil rights under racist Jim Crow laws (which for example banned interracial marriage, introduced literacy tests for voters, and segregated schools) and were subjected to violence from white supremacists during the nadir of American race relations. African Americans who moved to the North in order to improve their prospects in the Great Migration also faced barriers in employment and housing. Legal racial discrimination was upheld by the Supreme Court in its 1896 decision in Plessy v. Ferguson, which established the doctrine of "separate but equal". The movement for civil rights, led by figures such as W. E. B. Du Bois and Booker T. Washington, achieved few gains until after World War II. In 1948, President Harry S. Truman issued an executive order abolishing discrimination in the armed forces.

The United States National Security Council (NSC) is the national security council used by the president of the United States for consideration of national security, military, and foreign policy matters. Based in the White House, it is part of the Executive Office of the President of the United States, and composed of senior national security advisors and Cabinet officials.

Since its inception in 1947 by President Harry S. Truman, the function of the council has been to advise and assist the president on national security and foreign policies. It also serves as the president's principal arm for coordinating these policies among various government agencies. The council has subsequently played a key role in most major events in U.S. foreign policy, from the Korean War to the war on terror.

The Truman Doctrine is a U.S. foreign policy that pledges American support for U.S.-aligned nations against alleged authoritarian threats. The doctrine originated with the primary goal of countering the growth of the Soviet bloc during the Cold War. It was announced to Congress by President Harry S. Truman on March 12, 1947, and further developed on July 4, 1948, when he pledged to oppose the communist rebellions in Greece and Soviet demands on Turkey. More generally, the Truman Doctrine implied U.S. support for other nations threatened by Moscow. It led to the formation of NATO in 1949. Historians often use Truman's speech to Congress on March 12, 1947, to date the start of the Cold War.

Truman told Congress that "it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures." Truman contended that because totalitarian regimes coerced free peoples, they automatically represented a threat to international peace and the national security of the United States. Truman argued that if Greece and Turkey did not receive the aid, they would inevitably fall out of the United States' sphere of influence and into the communist bloc, with grave consequences throughout the region.

Containment was a geopolitical strategic foreign policy pursued by the United States during the Cold War to prevent the spread of communism after the end of World War II. The name was loosely related to the term cordon sanitaire, which was containment of the Soviet Union in the interwar period.

Containment represented a middle-ground position between détente (relaxation of relations) and rollback (actively replacing a regime). The basis of the doctrine was articulated in a 1946 cable by U.S. diplomat George F. Kennan during the post-World War II term of U.S. President Harry S. Truman. As a description of U.S. foreign policy, the word originated in a report Kennan submitted to US Defense Secretary James Forrestal in 1947, which was later used in a Foreign Affairs article.

The 1954 Guatemalan coup d'état (Spanish: Golpe de Estado en Guatemala de 1954) deposed the democratically elected Guatemalan president Jacobo Árbenz and marked the end of the Guatemalan Revolution. The coup installed the military dictatorship of Carlos Castillo Armas, the first in a series of U.S.-backed authoritarian rulers in Guatemala. The coup was precipitated by a CIA covert operation code-named PBSuccess.

The Guatemalan Revolution began in 1944, after a popular uprising toppled the military dictatorship of Jorge Ubico. Juan José Arévalo was elected president in Guatemala's first democratic election. He introduced a minimum wage and near-universal suffrage. Arévalo was succeeded in 1951 by Árbenz, who instituted land reforms which granted property to landless peasants. The Guatemalan Revolution was disliked by the U.S. federal government, which was predisposed during the Cold War to see it as communist. This perception grew after Árbenz had been elected and formally legalized the communist Guatemalan Party of Labour. The U.S. government feared that Guatemala's example could inspire nationalists wanting social reform throughout Latin America. The United Fruit Company (UFC), whose highly profitable business had been affected by the softening of exploitative labor practices in Guatemala, engaged in an influential lobbying campaign to persuade the U.S. to overthrow the Guatemalan government. U.S. president Harry S. Truman authorized Operation PBFortune to topple Árbenz in 1952, which was a precursor to PBSuccess.