Cold War is the term used to describe the intense rivalry that developed after World War II between groups of Communist and non-Communist nations. On one side were the Union of Soviet Socialist Republics (U.S.S.R.) and its Communist allies, often referred to as the Eastern bloc. On the other side were the United States and its democratic allies, usually referred to as the Western bloc. The struggle was called the Cold War because it did not actually lead to fighting, or "hot" war, on a wide scale.

The Cold War was characterized by mutual distrust, suspicion, and misunderstandings by both the United States and the Soviet Union, and their allies. At times, these conditions increased the likelihood of a third world war. The United States accused the Soviet Union of seeking to expand Communism throughout the world. The Soviets, meanwhile, charged the United States with practicing imperialism and with attempting to stop revolutionary activity in other countries. Each bloc's vision of the world also contributed to East-West tension. The United States wanted a world of independent nations based on democratic principles. The Soviet Union, however, attempted to tightly control areas it considered vital to its national interest, including much of Eastern Europe.

Though the Cold War did not begin until the end of World War II, in 1945, relations between the United States and the Soviet Union had been strained since 1917. In that year, a revolution in Russia established a Communist dictatorship there. During the 1920's and the 1930's, the Soviets called for world revolution and the destruction of capitalism, which was the economic system of the United States. The United States did not grant diplomatic recognition to the Soviet Union until 1933.

In 1941, during World War II, Germany attacked the Soviet Union. The Soviet Union then joined the Western Allies in fighting Germany. For a time early in 1945, it seemed possible that a lasting friendship might develop between the United States and the Soviet Union based on their wartime cooperation. However, major differences continued to exist between the two, particularly with regard to Eastern Europe. As a result of these differences, the United States adopted a "get tough" policy toward the Soviet Union after the war ended. The Soviets responded by accusing the United States and the other capitalist allies of the West of seeking to encircle the Soviet Union so they could eventually overthrow its Communist form of government.

Two great blocs came into being. The United States led the Western bloc. By the early 1950's, this group included Britain, Canada, France, West Germany, Japan, the Philippines, and many other countries of Western Europe and Latin America. The Soviet Union led the Eastern bloc, which included Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, and Romania. China joined the Eastern bloc following the Communist take-over of its government in 1949. The nonaligned or neutral nations--those in neither bloc--included India, Indonesia, Cambodia, and most of the African states.

During the late 1940's and the 1950's, the Cold War became increasingly tense. Each side accused the other of wanting to rule the world. Each side believed its political and economic systems were better than the other's. Each strengthened its armed forces. Both sides viewed the Cold War as a dispute between right and wrong. They saw every revolt and every international incident as part of the Cold War. This situation made it difficult to settle any dispute peacefully through compromise, with each side giving up something. Fear grew among all peoples that a local conflict would touch off a third world war that might destroy humanity.

The nature of the Cold War began to change in the 1960's. Neither the East nor the West remained a monolith (united bloc). Communist China challenged Soviet leadership. China accused the Soviet Union of betraying Communism and being secretly allied with the United States. Some Communist countries followed China's leadership, and others remained loyal to the U.S.S.R.

Among the nations of the Western bloc, France harshly criticized many U.S. policies and demanded independent leadership in Europe. West Germany also acted independently of U.S. policies. It searched for new economic and political relationships with other European countries, including East Germany.

Economic developments caused major shifts in the world balance of power during the 1960's. The rapid industrialization of Japan and West Germany made them important nations in the struggle for power. Their emergence and the growing strength of China led to new relationships. In 1970, Soviet and West German leaders signed a treaty pledging peaceful relations between their nations. The long-disputed status of West Berlin was settled in 1971 when Britain, France, the Soviet Union, and the United States agreed that the city was not part of West Germany. But the four powers also provided for economic and political ties between West Berlin and West Germany. Also in 1971, China joined the United Nations (UN). The United States established diplomatic relations with China in 1979.

Cold War tensions rose again after the Soviet Union invaded Afghanistan in 1979. Soviet leaders said the invasion was designed to help defend Afghanistan's pro-Communist government from Afghan rebels. In the late 1980's, however, Cold War tensions began to ease sharply after the signing of a major U.S.-Soviet arms-control agreement and after the U.S.S.R. removed its troops from Afghanistan.

Tensions further decreased after major democratic reforms took place in Eastern Europe. In 1991, the Soviet Union broke up into a number of independent, non-Communist states. These reforms and other developments marked the end of the Cold War.

The coming of the Cold War

Historians do not agree on exactly when the Cold War began. But most agree that the Yalta Conference, a meeting of Allied leaders in February 1945, marked the high point of wartime good will between the United States and the Soviet Union. Most historians also agree that relations between the two countries deteriorated noticeably within the first year after the conference.

The alliance breaks up. With Germany nearly defeated, the leaders of the Big Three nations met at the Yalta Conference to plan for the peace that would follow the war. These leaders were President Franklin D. Roosevelt of the United States, Prime Minister Winston Churchill of Great Britain, and Premier Joseph Stalin of the Soviet Union. At Yalta, the leaders agreed to set up occupation zones (areas controlled by the Allies) for postwar Germany and made plans to form the United Nations. In addition, Stalin promised that the U.S.S.R. would go to war against Japan within three months after Germany surrendered.

The Allied leaders also developed the Declaration on Liberated Europe, in which they pledged to hold democratic elections in countries freed from the control of Germany and its allies. The Soviet Union failed, however, to keep this agreement. At the time it was made, Soviet forces had driven German troops out of most of Eastern Europe and had established a pro-Communist government in Poland. In spite of the Declaration on Liberated Europe, Stalin was determined to maintain tight control over Eastern Europe. He especially felt that control of Poland, which had been used as a route to invade the Soviet Union, was necessary to Soviet security. The United States felt betrayed by Stalin's refusal to carry out all of his promises and by his determination to establish a "sphere of influence" in Eastern Europe.

Roosevelt died in April 1945 and was succeeded as President by Harry S. Truman. Germany surrendered in May 1945. The main Allied leaders met for the final time at Potsdam, near Berlin, in July 1945. Just before the meeting, Churchill's Conservative Party was defeated in an election. Clement R. Attlee succeeded Churchill during the Potsdam Conference.

At Potsdam, the Allies agreed that the German people should be allowed to rebuild their lives "on a democratic and peaceful basis." However, serious disagreements arose. Great Britain and the United States charged that the U.S.S.R. was communizing the countries of Eastern Europe. Even before World War II ended, the U.S.S.R. had taken over the Baltic states of Latvia, Estonia, and Lithuania; parts of Poland, Finland, and Romania; and eastern Czechoslovakia. Soviet troops occupied a third of Germany and all of Bulgaria, Hungary, Poland, and Romania. Nevertheless, the Western nations reluctantly agreed to a Soviet-backed transfer of 40,000 square miles of German territory to Polish control.

The Iron Curtain descends. During 1945 and early in 1946, the Soviet Union cut off nearly all contacts between the West and the occupied territories of Eastern Europe. In March 1946, Churchill warned that "an iron curtain has descended across the Continent" of Europe. He made popular the phrase Iron Curtain to refer to Soviet barriers against the West. Behind these barriers, the U.S.S.R. steadily expanded its power.

In 1946, the U.S.S.R. organized Communist governments in Bulgaria and Romania. In 1947, Communists took control of Hungary and Poland. Communists seized full power in Czechoslovakia early in 1948. These countries became Soviet satellites (nations controlled by the U.S.S.R.).

Albania already had turned to Communism. Enver Hoxha, who led the Communist National Liberation Army in an Albanian civil war during World War II, established a Communist government in 1944.

Yugoslavia also joined the Communist bloc. The Communist Party of Yugoslavia had helped drive out the Germans near the end of the war. Communists led by Josip Broz Tito then took over the government.

East and West opposed each other in the United Nations. In 1946, the U.S.S.R. rejected a U.S. proposal for an international agency to control nuclear energy production and research. The Soviet Union believed the United States had a lead in nuclear weapons and would have a monopoly if controls were approved. The Soviet Union pictured itself as a defender of peace and accused the United States of planning a third world war.

The West holds the line

The Containment Policy. In the fall of 1946, Greek Communists revolted against the Greek government. Great Britain had been giving military and economic aid to Greece. But the British told the United States they could no longer give enough help to the Greeks. The British also warned that they could not help Turkey resist Communist pressure.

In March 1947, President Truman declared that the United States would help any free nation resist Communist aggression (attack). Congress granted his request for $400 million for aid to Greece and Turkey. With this aid, both Greece and Turkey successfully resisted Communism. The new American policy became known as the Truman Doctrine. Aimed at Soviet expansion in Europe, the Truman Doctrine developed into the Containment Policy. The Containment Policy was designed to contain (hold back) the expansion of Communism throughout the world.

The foreign ministers of the United States, Great Britain, France, and the Soviet Union met in Moscow in March and April 1947. They tried to draw up a German peace treaty. But the ministers could not agree on ways to end the occupation or on how to unify Germany.

The failure of the conference convinced U.S. Secretary of State George C. Marshall that the U.S.S.R. would not help Europe recover from World War II. In June 1947, Marshall proposed giving U.S. economic aid to all European nations that would cooperate in plans for their own recovery. This proposal grew into the European Recovery Program, or Marshall Plan, which began in 1948. The United States believed that a strong, stable Western Europe would block the spread of Communism. Meanwhile, in September 1947, the U.S.S.R. and eight other European Communist parties set up the Cominform, a new version of the Communist International.

Czechoslovakia and Poland wanted to take part in the Marshall Plan, but the U.S.S.R. would not let them accept U.S. aid. Instead, the Soviet Union set up the Council for Mutual Economic Assistance (COMECON) in January 1949. This organization was designed to unite the East European satellites economically and politically.

In June 1948, the Western Allies announced plans to unify their German occupation zones and establish the West German Federal Republic (West Germany). West Germany was formally established in September 1949. It had independence in some of its internal affairs, and it joined the Marshall Plan.

Also in June 1948, the U.S.S.R. harshly criticized Tito, the Communist leader of Yugoslavia. Tito then declared his country's independence from Soviet control.

The Berlin blockade was the Soviet answer to the West's plans for West Germany. In June 1948, Soviet troops blocked all railroad, highway, and water traffic through East Germany to West Berlin. The city lay 110 miles (177 kilometers) inside the Soviet occupation zone. The Soviet leaders thought their blockade would force the West to leave Berlin. Instead of pulling out of West Berlin, the Americans, British, and French set up the Berlin airlift. For 11 months, West Berlin was supplied with food and fuel entirely by airplanes. The U.S.S.R. lifted the blockade in May 1949. The Allies ended the airlift in September.

The West rearms. Military strength became more and more important in the late 1940's. During the Berlin blockade, the United States pledged continuing military aid to Western Europe. The United States, Canada, and 10 Western European nations signed the North Atlantic Treaty in April 1949. This mutual defense treaty set up the North Atlantic Treaty Organization (NATO), a military alliance. The goals of the alliance included the prevention of Soviet expansion and the defense of West Germany. In September 1951, the United States signed the ANZUS mutual defense treaty with Australia and New Zealand.

The nuclear arms race began on Aug. 29, 1949, when the Soviet Union tested an atomic bomb. Until then, the United States had been the only nation that knew how to make the atomic bomb.

Communist expansion in Asia. During the 1940's, Communist strength increased in the Far East. The U.S.S.R. had occupied Manchuria just before the end of World War II. After they left in 1946, the Chinese Communists took over most of northern Manchuria. The U.S.S.R. also set up a North Korean "people's republic."

In China, Mao Zedong's Communist troops fought the Nationalist armies of Chiang Kai-shek. The United States gave military aid to Chiang. Late in 1949, Chiang and his government fled to the island of Taiwan, near the mainland of China. The conquest of China by Mao's forces put China into the Communist bloc.

The Korean War. At the end of World War II, Soviet troops occupied North Korea and U.S. forces occupied South Korea. The North Koreans had a strong army. They got Soviet military aid even after Soviet troops withdrew from North Korea late in 1948. The United States withdrew its forces from South Korea in June 1949.

North Korean troops invaded South Korea on June 25, 1950, and the Korean War began. On June 27, President Truman sent U.S. forces to aid the South Koreans. At the request of the United States, the United Nations Security Council voted to send UN troops to help South Korea. The Soviet delegation was boycotting (not attending) the council, and missed a chance to veto the decision. Seventeen nations contributed men to the United Nations' force, and Chinese Communist troops aided the North Koreans.

Peace talks began in July 1951. They went on for two years while bloody fighting continued. Finally, in July 1953, representatives of the UN and the Communists signed an armistice. In 1954, representatives of both sides met in Geneva, Switzerland, to discuss a political settlement. But they could not agree on a way to unite North and South Korea.

The Korean War was the first war in which troops of a world organization fought an aggressor nation. For the first time, Americans fought a "hot war" against Communism. Some historians believe the Korean War was a major turning point in the Cold War. It extended the Containment Policy to the Far East. It also introduced limited warfare to the East-West conflict as a substitute to all-out--and possibly nuclear--war. Each side avoided attacking targets that could have led to expansion of the war. And each side limited the weapons it used and the territory in which it would fight.

To the brink and back

The death of Stalin changed the character of the Cold War. The Soviet leader died in March 1953, two months after Dwight D. Eisenhower became President of the United States. The new Soviet rulers governed as a committee at first. Premier Georgi M. Malenkov and his associates adopted a softer policy toward the Soviet satellites and the West. For example, they allowed the Soviet wives of U.S. servicemen to follow their husbands to America. The U.S.S.R. also set up a cultural exchange program with the West. Soviet troops put down a revolt in East Germany in June 1953, but the Soviet Union's softer course of action was obvious.

The arms race continued. The United States tested its first hydrogen bomb in November 1952, and the U.S.S.R. set off its first H-bomb in November 1955. Military alliances were strengthened during this period. Also in 1955, West Germany joined NATO. In response, the U.S.S.R. and its Eastern European satellites signed the Warsaw Mutual Defense Pact, a military alliance. In 1955, the United States announced its support of the military alliance of the Baghdad Pact, which later became the Central Treaty Organization.

In January 1954, the new U.S. secretary of state, John Foster Dulles, had outlined a new American military policy. The United States, he warned, would meet Communist aggression by "massive retaliation" with nuclear weapons. The United States, Dulles said, would strike back "at places and with means of our own choosing."

Cold War tensions increased in eastern Asia during 1954 and 1955. The nationalist Vietnamese in Indochina were led by Communists and supported by China. In the spring of 1954, after years of fighting, they defeated the French at Dien Bien Phu. A cease-fire agreement was signed in Geneva in July 1954. It recognized the temporary division of Vietnam and gave North Vietnam to the Communists. Nationwide elections were to be held in 1956. However, neither the United States nor South Vietnam signed the agreement, and South Vietnam refused to hold the elections. The agreement also established the independence of Cambodia, Laos, and South Vietnam.

In September 1954, the United States and seven other nations signed the Southeast Asia Collective Defense Treaty. This treaty was designed to prevent further Communist expansion in Southeast Asia. After the defeat of France in Indochina, the United States increased its aid to South Vietnam. The United States believed that if one Southeast Asian nation fell to Communism, the others would also topple over, one after another. This was called the "domino theory." But even with U.S. support, South Vietnam could not defeat the Communist rebels. The rebels, called Viet Cong, were supported by North Vietnam. In 1955, the United States began sending military advisers to help the South Vietnamese government.

The United States also increased its support of the Chinese Nationalists on Taiwan. In September 1954, the Chinese Communists staged air and artillery attacks against the islands of Quemoy and Matsu. These islands, in the Formosa Strait, were held by the Nationalist Chinese. In 1955, Congress voted to let President Eisenhower use armed force if necessary to protect the Chinese Nationalists.

The spirit of Geneva. In Europe, a thaw in the Cold War became apparent in 1955. The Western Allies and the U.S.S.R. signed a peace treaty with Austria in May. Soviet troops left that country, and Austria became an independent, neutral nation. That same month, Nikita S. Khrushchev, the Soviet Communist Party chief, apologized to Tito and resumed trade with Yugoslavia.

Eisenhower and Khrushchev met in Geneva in July. Both leaders agreed that a nuclear war would be a disaster for both sides. Political observers began to write of a "big thaw" in East-West relations and called it the "spirit of Geneva." After the Geneva conference, the U.S.S.R. announced a cut of 640,000 men in its armed forces. The Soviet Union said it also had reduced the armies of its satellites.

Dulles still distrusted the Soviet Union in spite of its softer line. In January 1956, he told the American people that the United States had been on the brink of war several times. "If you are scared to go to the brink, you are lost," Dulles warned. The use of "brinkmanship" had become part of U.S. policy.

In February 1956, Khrushchev called for peaceful coexistence (competition without war) between East and West. He also began a campaign of destalinization (removal of Stalinist influences) in the U.S.S.R. and its satellites. In April 1956, the U.S.S.R. dissolved the Cominform.

Unrest in Eastern Europe. The new Soviet policy encouraged the peoples of Eastern Europe to expect more freedom from Soviet rule. In Poland, riots and strikes broke out in Poznan in June 1956, and spread to other cities. The rioters demanded a more liberal government and an end to Soviet rule. A few months later, the U.S.S.R. allowed Wladyslaw Gomulka, a Polish Communist leader, to rejoin the Polish Communist Party. The U.S.S.R. had jailed Gomulka in 1951 for trying to set up an independent Communist government in Poland. Khrushchev and other Soviet leaders flew to Warsaw to confer with Gomulka in October 1956. Faced with further rebellion, the U.S.S.R. agreed to relax some controls in Poland.

In Hungary, a revolt against Communism began in October 1956. A rebel government led by Imre Nagy demanded withdrawal of all Soviet troops. Early in November, Soviet tanks rolled into Budapest. The fighting spread to all parts of the country, and thousands of Hungarian "freedom fighters" were killed. The Soviet Union smashed the revolt in about two weeks. In spite of the new Soviet policy, the Soviet Union could not allow Hungary to break up the bloc of Eastern European satellites.

Trouble at Suez. During the period that the U.S.S.R. was putting down unrest in its Eastern European satellites, trouble was stirring in the Middle East. The United States feared Communist expansion in that area. Both the U.S.S.R. and the West sought Egypt's support by offering aid for its development plans. Each side offered to help build the Aswan High Dam. After Egypt courted Communist aid for the dam and bought Communist arms, the United States and Great Britain canceled offers to help with the project. President Gamal Abdel Nasser of Egypt struck back by seizing the Suez Canal from international control. He said Egypt would use profits from operating the canal to build the dam "without pressure from any nation." But he did accept Soviet aid.

In October 1956, while the U.S.S.R. was involved with the Hungarian revolt, Israel invaded Egypt. Britain and France immediately joined in the attack. They wanted to return the Suez Canal to international control. The United States and the U.S.S.R. supported a United Nations resolution demanding an immediate truce. In addition, the U.S.S.R. threatened to send troops to help Egypt. The UN arranged a truce after a few days of fighting. But the U.S.S.R., by backing Egypt against Israel, had won friends among the Arab nations of the Middle East.

New challenges

Khrushchev's power in the Soviet Union reached its peak in the late 1950's. Sometimes the U.S.S.R. followed a hard policy, mainly in response to China's challenge to Soviet leadership of the Communist bloc. At other times, the U.S.S.R. stressed peaceful coexistence, giving special attention to economic aid and scientific progress. But the Soviet Union continued to encourage "wars of liberation." As a result, the United States came to regard "peaceful coexistence" as the Communist effort to conquer countries without a major war.

The missile gap. The U.S.S.R. improved its ability to produce nuclear weapons, and the Western bloc feared a missile gap, or Soviet rocket superiority. In June 1957, the U.S.S.R. successfully tested an intercontinental ballistic missile (ICBM). That same year, the U.S.S.R. launched the first artificial earth satellite, Sputnik 1. In January 1958, the United States launched its first earth satellite. Soviet rocket power was more advanced, but the two powers had clearly established a nuclear "balance of terror." A brief thaw in the Cold War followed. The U.S.S.R. stopped testing nuclear weapons in March 1958, and the United States halted its tests in October.

The Eisenhower Doctrine was approved by Congress in March 1957 because the United States feared Communist penetration in the Middle East. This policy permitted the President to "use armed force to assist any ... nation ... [in the Middle East] requesting assistance against armed aggression from any country controlled by international Communism."

In July 1958, a revolution ended the rule of the pro-Western government of Iraq. Nearby Lebanon feared a Communist revolution and asked the United States for aid. Eisenhower quickly sent about 6,000 sailors and marines to help Lebanon. Great Britain sent paratroopers to protect Jordan against Iraqi pressure. In spite of Soviet protests, the American and British forces stayed in the Middle East for about three months.

The Far East. In 1958, the Chinese Communists again fired on Quemoy and Matsu, Taiwan's offshore islands. Dulles warned that any attack on these islands would be considered aggression against Nationalist China, a U.S. ally. But occasional firing continued during the 1960's.

Germany. During the late 1950's, Europe remained the most important Cold War battleground. The U.S.S.R. tried repeatedly to damage the reputation of the West in Germany. In November 1958, the U.S.S.R. demanded peace treaties for East and West Germany. Such treaties would have ended the military occupation, and Western troops would have had to leave. The United States refused to yield to the demand, and kept its forces in Berlin. As a result, the U.S.S.R. kept threatening to sign a separate peace treaty with East Germany.

The spirit of Camp David. Another temporary thaw in the Cold War began in the spring of 1959. The foreign ministers of the United States, Great Britain, France, and the U.S.S.R. met in May. In July, Vice President Richard M. Nixon visited the U.S.S.R. and met with Khrushchev. Two months later, Khrushchev visited the United States. He conferred with Eisenhower at Camp David in Maryland. Khrushchev was so friendly that observers spoke of the "spirit of Camp David," recalling the earlier "spirit of Geneva." Eisenhower and Khrushchev discussed a summit (top-level) conference to be held in Paris in 1960. The President accepted Khrushchev's invitation to visit the Soviet Union after the summit meeting.

The U-2 incident abruptly ended the thaw. An American U-2 spy plane was shot down in the U.S.S.R. in May 1960. The Soviet Union captured the pilot, Francis Gary Powers, who confessed he was a spy. Eisenhower accepted personal responsibility for the flight. He admitted that U-2 planes had been flying over the U.S.S.R. taking photographs for four years.

When the summit conference began on May 15, Khrushchev demanded that Eisenhower apologize for the U-2 incident. Eisenhower refused, and Khrushchev angrily canceled his invitation for the President to visit the U.S.S.R.

Africa. The Cold War struggle moved to Africa in July 1960. Premier Patrice Lumumba of the Congo asked the UN to deal with a revolt in his newly independent nation. He charged that the Belgians were aiding the rebel Katangans. The U.S.S.R. sided with Lumumba against a group led by Congolese President Joseph Kasavubu. The UN intervened in the dispute, keeping the U.S.S.R. and the West from direct military action. The Soviet Union charged that the UN favored the West.

The troika proposal. In September 1960, Khrushchev went to New York City for the meeting of the UN General Assembly. He again criticized the United States for the U-2 flights. The Soviet leader showed his anger by taking off a shoe and pounding his desk with it.

Khrushchev tried to destroy the power of the UN to send troops into trouble spots. He called for three secretaries-general--a troika (a Russian term for a vehicle drawn by three horses)--to replace the UN secretary-general. One of the secretaries-general would be a Communist, one from a neutral nation, and one from the West. The General Assembly defeated the proposal.

The Bay of Pigs. John F. Kennedy became President of the United States in January 1961. Cold War tensions were high--in Europe, in Asia, and even on the doorstep of the United States, in Cuba.

The Cuban government of Fidel Castro had become openly Communist in 1960. Castro condemned the United States and began to receive military aid from the Soviet Union and other Communist countries. The Cuban government seized millions of dollars' worth of American property in Cuba. The United States ended diplomatic relations with Cuba in January 1961.

In April 1961, the United States sponsored an invasion of Cuba by anti-Castro Cubans at the Bay of Pigs. The attack was poorly planned and failed badly. The unsuccessful invasion strengthened Castro's control of Cuba, and it caused the United States to lose face.

The Berlin Wall. Kennedy and Khrushchev met in Vienna, Austria, in June 1961. Khrushchev demanded a free Berlin and an end of the military occupation. The two leaders failed to reach agreement, and Khrushchev again threatened to sign a separate peace treaty with East Germany. In July 1961, the U.S.S.R. canceled cuts in its armed forces and increased military spending.

Growing numbers of East Germans were fleeing to West Germany. On Aug. 13, 1961, the East German Communists began to build a wall of cement and barbed wire between East and West Berlin. To confirm the right of the Western powers to remain in West Berlin, the United States sent troops to the city by highway. U.S. tanks enforced Western rights to enter East Berlin without showing papers to Communist border guards. Some East Germans escaped to West Berlin after the wall was built, but many were killed in the attempt.

The space race begins. On Oct. 4, 1957, the Soviet Union launched Sputnik 1, the first artificial satellite. Several months later, on Jan. 31, 1958, the United States launched its first satellite, Explorer 1. In 1961, the two countries each launched their first manned spacecraft.

In September 1961, the U.S.S.R. ignored an unofficial agreement against nuclear weapons tests, and resumed nuclear bomb testing in the atmosphere. The United States then resumed underground testing. American tests above ground were started again in April 1962.

The Cuban missile crisis. In October 1962, the United States learned that the U.S.S.R. had secretly installed missiles and missile bases in Cuba, about 90 miles from Florida. President Kennedy demanded that the U.S.S.R. remove them. He set up naval "quarantine" of Cuba. The U.S.S.R. said that it would not remove the missiles unless the United States removed its nuclear missiles from Turkey. Kennedy privately agreed to the proposal. After a week of extreme tension, Khrushchev removed the Soviet missiles.

Easing Cold War tensions

After the missile crisis in Cuba, Cold War tensions again eased. In July 1963, the United States, the U.S.S.R., and Britain approved a treaty to stop the testing of nuclear weapons in the atmosphere, in outer space, and under water. In August, the United States and the U.S.S.R. set up a hot line between the White House and the Kremlin. This direct communications link was installed to reduce the risk of accidental nuclear war.

In 1963, the U.S.S.R. faced a serious shortage of grain. Kennedy approved a plan to sell the U.S.S.R. $250 million worth of American wheat. That same year, the two nations agreed to cooperate in space projects using weather and communications satellites.

President Lyndon B. Johnson, who became Chief Executive after Kennedy was assassinated in November 1963, continued to work for peaceful coexistence. In 1964, the United States and the U.S.S.R. signed their first bilateral (two-nation) treaty. It provided that a consul (representative) of each nation would have an office in a city of the other country. It also provided protection for Americans traveling in the U.S.S.R. and for Soviet citizens traveling in the United States. The U.S. Senate approved the treaty in 1967, and the U.S.S.R. approved it in 1968. The two nations also extended an agreement for educational, scientific, and cultural exchanges.

The shifting Cold War battleground

The character of the Cold War changed again in the mid-1960's. The United States and the U.S.S.R. each had large numbers of nuclear weapons. Each had an antimissile defense system. But both powers realized that there would be no victor in an all-out nuclear war. Also, conflicts within both the Eastern and Western blocs changed the two-sided nature of the balance of power.

The great blocs split. Following the Soviet Union's destalinization campaign, the U.S.S.R. and Communist China began to move along different paths. In 1960, at the third Congress of the Romanian Communist Party, the U.S.S.R. and China quarreled bitterly and openly. The Soviet Union soon cut off technical aid to China. When China attacked India in 1962, the U.S.S.R. supported India. The Soviet Union again backed India when Pakistan and India fought in 1965. China threatened India and aided Pakistan.

Khrushchev fell from power in October 1964. The new Soviet leaders tried to heal the split with China. But Premier Aleksei N. Kosygin and General Secretary Leonid I. Brezhnev were unable to reunite the Communist bloc.

In 1966, China launched a "cultural revolution." One aim of this revolution was to eliminate all Soviet influence from China. The Chinese accused the Soviet Union of betraying world Communism and being secret allies of the United States. The Chinese threat to the Soviet Union became more real when China exploded its first hydrogen bomb in June 1967.

In March 1969, Soviet and Chinese troops began to fight each other on an island in the frozen Ussuri River. This river is the border between Chinese Manchuria and the Soviet Union's maritime territories. Both countries claimed they owned the island. The fighting soon ended, but the border controversy remained unsettled.

Some of the Soviet Union's satellites also shifted their loyalty. Albania had sided with China in 1961, and neither China nor Albania attended the 23rd Communist Party Congress in Moscow in 1965. Yugoslavia remained independent, with its own brand of "national Communism." Other Communist nations, including Romania, Poland, and Cuba, loosened their ties with the U.S.S.R.

Differences also sharpened among the Western nations. President Charles de Gaulle of France challenged the leadership of the United States and Great Britain. France established diplomatic relations with China in 1964, and sharply criticized U.S. policy in the Vietnam War. At de Gaulle's request, NATO moved its military headquarters from France in 1967, and the French withdrew their troops from the alliance. France also blocked Great Britain's entry into the European Economic Community (EEC). In 1967, de Gaulle further strengthened France's relations with the U.S.S.R. and Eastern Europe. In June of that year, France sided with the Arabs against Israel in the Arab-Israeli War. In 1968, France exploded a hydrogen bomb.

The growing strength of Europe was another factor in the changing nature of the Cold War. More than 20 years after the end of World War II, the nations of Western Europe were enjoying prosperity. The EEC, also called the European Common Market, had become a powerful economic force. Western European nations gradually increased trade with Communist countries. Many Western European leaders worried more about Germany's return to power than about the U.S.S.R.

Soviet-American relations in the 1960's reflected the changing nature of the Cold War. In 1966, the U.S.S.R. and the United States agreed to permit direct air service between Moscow and New York City. By January 1967, they and 60 other nations had signed the first international treaty providing for the peaceful exploration and use of outer space.

President Johnson and Premier Kosygin met for the first time in June 1967. Kosygin went to the United States to address the UN General Assembly. The two leaders met in Glassboro, N.J., and discussed the Vietnam War, the Arab-Israeli dispute, and disarmament.

In August 1967, the U.S.S.R. and the United States submitted proposals at the Geneva Disarmament Conference for a treaty to prevent the spread of nuclear weapons. In 1968, they agreed on an addition to the treaty providing for international inspection and controls. France refused to sign the treaty. The U.S. Senate approved it in 1969. The treaty, called the Treaty on the Non-Proliferation of Nuclear Weapons, went into effect on March 5, 1970, after being ratified (formally approved) by the United States, the U.S.S.R., Britain, and more than 40 other nations. Since then, over 100 additional nations have ratified it.

In 1969, Soviet and U.S. representatives began a series of Strategic Arms Limitation Talks (SALT). The representatives worked toward an agreement to control the production of nuclear weapons.

The invasion of Czechoslovakia. Hopes for an easing of Cold War tensions in Europe were jolted in August 1968, when Soviet, Bulgarian, East German, Hungarian, and Polish troops invaded Czechoslovakia. The invasion halted a move by Czechoslovakia to give more individual freedom to the its people. In October, Czechoslovakia and the U.S.S.R. signed a treaty that allowed Soviet troops to remain and assured that Czechoslovakia would continue as a Soviet satellite.

The battle for the neutral nations continued in the 1960's. In Latin America, the United States still guarded against the threat of Communism. In April and May 1965, the United States, at the request of the Dominican Republic, sent troops to the Dominican Republic to prevent a Communist take-over during a revolt there. The crisis eased, and the United States troops left.

In the Middle East, a six-day war broke out between Israel and the Arab powers in June 1967. The United States backed the Israelis. The U.S.S.R. helped arm the Arabs before the war began, but this did not prevent their defeat. Scattered fighting continued in the area during the late 1960's. The United States and the U.S.S.R. increased aid to the opposing sides. In Africa, most of the newly independent nations remained neutral. They took aid from all the major Cold War powers.

The Vietnam War threatened to turn the Cold War into a general hot war. During the early 1960's, the United States stepped up its support of South Vietnam against the Communist Viet Cong forces. The United States blamed the struggle on Communist North Vietnam, viewing the war as "aggression from the north."

The United States gradually escalated (increased) its military effort. In 1965, it began large-scale bombing of North Vietnam. By 1968, over 500,000 U.S. troops were in Vietnam. The Viet Cong and North Vietnamese received war materials from the Soviet Union and China.

The fighting spread throughout Indochina. Cambodia and Laos, both of which bordered South Vietnam, tried to stay neutral. But Communist forces used both countries as bases for raids into South Vietnam, and the two nations were drawn into the war. Thailand backed the West in the struggle. The United States used bases there for bombing raids on North Vietnam.

Peace talks started in Paris in May 1968. But the talks stalled, and the fighting went on. In 1969, the United States established new training programs to help the South Vietnamese take over most of the fighting. This policy became known as Vietnamization. Also in 1969, President Richard M. Nixon began to gradually reduce the number of U.S. soldiers in Vietnam. In 1973, the United States completed its withdrawal of ground forces. The war ended in 1975, after Communist troops conquered South Vietnam.

The Cold War in the 1970's

The loosening of ties among members of both the Communist and Western blocs during the 1960's led to new international relationships in the 1970's. Several Communist and democratic nations developed friendlier relations with one another, helping ease tensions.

In 1970, West Germany and Poland signed a treaty to reject the use of force and to recognize the boundaries created in Europe after World War II. West Germany and the Soviet Union ratified a similar treaty in 1972.

The status of West Berlin, a major Cold War problem, was settled in the early 1970's. France, Britain, the U.S.S.R., and the United States signed an agreement in 1971 stating that West Berlin was not part of West Germany. The Berlin agreement also allowed free movement of traffic between West Germany and West Berlin. The pact took effect in 1972, after details were worked out. In 1973, East and West Germany joined the UN.

Also in 1973, Britain finally entered the European Community. The increased economic ties among the organization's member nations made Western Europe a powerful, independent force in world affairs. Japan also began acting more independently of U.S. policies.

China's relations with the West improved in the early 1970's. Canada and several other Western nations established diplomatic relations with Communist China for the first time. China was admitted to the UN in October 1971. In February 1972, Nixon visited China for seven days. During the visit, Nixon and Chinese Premier Zhou Enlai agreed to increase contacts between their two countries. In 1979, the United States and China established diplomatic relations. As part of the agreement, the United States ended diplomatic ties with Taiwan.

In 1972, Nixon and Soviet leader Leonid I. Brezhnev signed two agreements, together known as SALT I, to limit the production of U.S. and Soviet nuclear weapons. SALT stands for Strategic Arms Limitation Talks. In 1979, the two countries signed another pact, SALT II, limiting long-range bombers and missiles. But SALT II did not go into effect officially. The U.S. Senate stopped considering the treaty after Soviet troops invaded Afghanistan in late 1979 and early 1980.

The Cold War after 1980

Cold War tensions increased in the early 1980's. The renewed friction resulted chiefly from the Soviet intervention in Afghanistan and from continued American fear of Soviet and Cuban influence in the Middle East, Southeast Asia, Africa, and Central America. U.S. President Ronald Reagan and his Administration adopted a policy they called linkage, tying any U.S. arms agreement to consideration of Soviet expansion.

Meanwhile, the growing military power of the Soviet Union led the United States to increase its defense budget. Many observers thought the U.S. defense build-up would lead to a more dangerous nuclear arms race. But events in the late 1980's led to a sharp reduction in U.S.-Soviet tensions. In 1987, Reagan and Soviet leader Mikhail Gorbachev signed a treaty to eliminate many of the ground-launched, nuclear missiles of both nations. The treaty went into effect in 1988. In 1988 and 1989, the U.S.S.R. withdrew its troops from Afghanistan. Also in the late 1980's, the Soviet Union began to reduce its conventional military forces in Eastern Europe. In the U.S.S.R., Gorbachev worked for a more decentralized economic system and allowed more democracy and freedom of expression. He also encouraged similar actions in Eastern Europe.

Beginning in 1989, Communist rule came to an end in a number of Eastern European countries, including Poland, Hungary, East Germany, and Czechoslovakia. In addition, East Germany began to allow its people to pass freely to West Berlin through the Berlin Wall, and the East Germans soon began to tear the wall down. Germany was reunified in 1990, when East Germany united with West Germany. In 1991, the Soviet Communist Party lost control of the Soviet government. Later that year, the Soviet Union was dissolved, and the republics that made up the nation became independent states. Russia was by far the largest of these states. In 1992, Russian President Boris Yeltsin and U.S. President George Bush formally declared that their countries did not regard each other as potential enemies. These events marked the end of the Cold War.