US Policy of Containment

What does US paranoia about the spread of communism in Asia in the 1940s have to do with the division and tensions between China and Taiwan today? 

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US Policy of Containment


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What does US paranoia about the spread of communism in Asia in the 1940s have to do with the division and tensions between China and Taiwan today?

The US policy of containment was used to prevent the spread of communism. Rather than intervening in countries that were already communist-ruled, the US tried to protect non-communist countries that were vulnerable to invasion or communist ideology. Whilst this policy was used around the world, in this article, we’ll focus specifically on why and how the US used it in Asia.

The capitalist US and Containment Policy in the Cold War

Containment was the cornerstone of US foreign policy during the Cold War. Let's define it before looking at why the US thought containment was necessary in Asia.

Containment definition in US history

The US Containment Policy is most often associated with the Truman Doctrine of 1947. President Harry S. Truman established that the US would provide:

political, military, and economic assistance to all democratic nations under threat from external or internal authoritarian forces.

This assertion then characterised the USA’s policy for much of the Cold War and led to US involvement in several overseas conflicts.

Why did the US pursue containment in Asia?

For the US, Asia was a potential breeding ground for communism after the Second World War. Theories surrounding the spread of communism and events after the War fueled the belief that a US policy of containment was necessary.

Event: the Chinese Revolution

In China, a civil conflict between the Chinese Communist Party (CCP) and the Nationalist Party, also known as Kuomintang (KMT), had been raging since the 1920s. World War II briefly halted this, as the two sides united to fight Japan. However, as soon as the war was over, conflict broke out again.

On 1 October 1949, this war ended with the Chinese Communist leader Mao Zedong declaring the creation of the People’s Republic of China (PRC) and the Nationalists fleeing to the island province of Taiwan. China became a communist country with a small resistance population governing Taiwan. The US saw China as the most dangerous of the USSR’s allies, and as a result, Asia became a key battleground.

The US worried that China would quickly envelop surrounding countries and turn them into communist regimes. A policy of containment was a means of preventing this.

US Containment Photograph showing the founding ceremony of the People's Republic of China StudySmarterPhotograph showing the founding ceremony of the People's Republic of China, Wikimedia Commons.

Theory: the Domino Effect

The US firmly believed in the idea that if one state fell or turned to communism, others would follow. This idea was known as the Domino Theory. This theory informed the US decision to intervene in the Vietnam War and support the non-communist dictator in South Vietnam.

The theory was largely discredited when the communist party won the Vietnam War and Asian states did not fall like dominoes.

Theory: vulnerable countries

The US believed that countries facing dire economic crises and with low standards of living may be more likely to turn to communism, as it might lure them with promises of a better life. Asia, like Europe, had been devastated by the Second World War and was of particular concern to the US.

Japan, at the height of its expansion, had dominated the Pacific, Korea, Manchuria, Inner Mongolia, Taiwan, French Indochina, Burma, Thailand, Malaya, Borneo, the Dutch East Indies, the Philippines, and parts of China. As the Second World War continued and the allies prevailed over Japan, the US stripped these countries of resources. Once the war had ended, these states were left in a political vacuum and with ruined economies. Countries in this condition were, in US political opinion, vulnerable to communist expansion.

Political/ Power vacuum

A situation when a country or government has no identifiable central authority.

Examples of containment during the Cold War

The US took several approaches to contain communism in Asia. Below we will look at them briefly, before going into greater detail when we discuss Japan, China, and Taiwan.

Satellite Nations

To successfully contain communism in Asia, the US needed a satellite nation with strong political, economic, and military influence. This allowed them greater proximity, and therefore the ability to act quickly if a non-communist country was attacked. Japan, for example, was made a satellite nation for the US. This gave the US a base from which to exert pressure in Asia, helping to contain communism.

Satellite Nation/State

A country that is formally independent but under the domination of a foreign power.

Economic aid

The USA also used economic aid to contain communism and this worked in two main ways:

  1. Economic aid was used to help rebuild countries that had been ravaged during World War II, the idea being that they would be less likely to turn to communism if they were thriving under capitalism.

  2. Economic aid was given to anti-communist armies so they could defend themselves better. Supporting these groups meant that the US did not have to risk getting directly involved, but could still contain the spread of communism.

US military presence

Containment also focused on ensuring a US military presence in Asia to support countries in the event of an attack. Maintaining a US military presence prevented countries from falling, or turning, to communism. It also strengthened the communication between the US and Asian states and enabled them to keep a firm grip on events on the other side of the world.

Model states

The US created ‘model states’ to encourage other Asian countries to pursue the same path. The Philippines and Japan, for example, received economic support from the US and became democratic and prosperous capitalist nations. They were then used as ‘model states’ to the rest of Asia to exemplify how resistance to communism was beneficial to nations.

Mutual defence treaties

Like the formation of NATO in Europe, the US also backed their policy of containment in Asia with a mutual defence treaty; The South East Asian Treaty Organisation (SEATO). Signed in 1954, it consisted of the US, France, Great Britain, New Zealand, Australia, the Philippines, Thailand and Pakistan, and ensured mutual defence in case of attack. This came into force on 19 February 1955 and ended on 30 June 1977.

Vietnam, Cambodia and Laos were not considered for membership but were given military protection by protocol. This would later be used to justify US intervention in the Vietnam War.

The ANZUS pact

Fear of communist expansion extended beyond the realms of Asia itself. In 1951, the US signed a mutual defence pact with New Zealand and Australia, which felt threatened by the spread of communism to the North. The three governments pledged to intervene in any armed attack in the Pacific that threatened any one of them.

The Korean War and US Containment

After the Second World War, the USSR and the US divided the Korean peninsula at the 38th parallel. Failing to reach an agreement about how to unify the country, each established its own government, the Soviet-aligned Democratic People’s Republic of Korea and the western-aligned Republic of Korea.

The 38th parallel (north)

A circle of latitude that is 38 degrees north of the Earth’s equatorial plane. This formed the border between North and South Korea.

On 25 June 1950, the North Korean People’s Army invaded South Korea, attempting to take control of the peninsula. The United Nations and the US-supported South Korea and managed to push back against the North past the 38th parallel and near the Chinese border. The Chinese (who were supporting the North) then retaliated. Reports suggest that between 3-5 million people died during the three-year conflict until an armistice agreement in 1953, which left the borders unchanged but installed a heavily guarded demilitarised zone along the 38th parallel.

Armistice agreement

An agreement to end active hostilities between two or more enemies.

The Korean War confirmed US fears about the threat of communist expansion and made it more determined to continue a policy of containment in Asia. The US intervention to contain communism in the North had been successful and demonstrated its efficacy. Rollback was largely discredited as a strategy.


A US policy to turn communist countries back to capitalism.

US Containment of communism in Japan

From 1937–45 Japan was at war with China, known as the Second Sino-Japanese War. This began when China defended itself against Japanese expansion in its territory, which had begun in 1931. The US, Britain, and Holland supported China and placed an embargo on Japan, threatening it with economic ruin.

As a result, Japan joined the Tripartite Pact with Germany and Italy, began planning for war with the West, and bombed Pearl Harbor in December 1941.

After the Allied Powers had won World War II and Japan had surrendered, the USA occupied the country. General Douglas MacArthur became the Supreme Commander of the Allied Powers (SCAP) and oversaw post-war Japan.

Japan’s importance

After the Second World War, Japan became a strategically important country for the US. Its location and industry made it important for trade and for exerting American influence in the region. A re-armed Japan gave Western allies:

  • Industrial and military resources.

  • The potential for a military base in North-East Asia.

  • Protection for US defensive outposts in the Western Pacific.

  • A model state that would encourage other states to fight against communism.

The US and its allies feared a communist take-over of Japan, which might provide:

  • Protection for other communist-controlled countries in Asia.

  • Passage through the US defences in the Western Pacific.

  • A base from which to launch an aggressive policy in South Asia.

After the Second World War, Japan had no political system, high casualties (around three million, which constitutes 3% of the 1939 population),¹ food shortages, and widespread devastation. Looting, the emergence of black markets, spiralling inflation and low industrial and agricultural output plagued the country. This made Japan a prime target for communist influence.

US Containment Photograph showing Okinawa destruction in 1945 StudySmarterPhotograph showing Okinawa destruction in 1945, Wikimedia Commons.

US Containment in Japan

The US progressed through four stages in its administration of Japan. Japan was not governed by foreign troops but by the Japanese government, instructed by the SCAP.


Reconstruction processes

Punish and reform (1945–46)

After the surrender in 1945, the US wanted to punish Japan but also reform it. During this period, the SCAP:

  • Removed the military and dismantled Japan’s armament industries.

  • Abolished nationalist organisations and punished war criminals.

  • Released political prisoners.

  • Broke up elite Zaibatsu families. These were families that organised large capitalist enterprises in Japan. They would often operate many companies, meaning they were wealthy and powerful.

  • Granted the Japan Communist Party legal status and allowed trade unions.

  • Repatriated millions of Japanese troops and civilians.

The ‘Reverse Course’ (1947–49)

In 1947 as the Cold War emerged, the US started to reverse some of its policies of punishment and reform in Japan. Instead, it began rebuilding and remilitarising Japan, aiming to create a key Cold War ally in Asia. During this period, SCAP:

  • Depurged nationalist and conservative wartime leaders.

  • Ratified a new Constitution of Japan (1947).

  • Restricted and tried to weaken trade unions.

  • Allowed the Zaibatsu families to reform.

  • Began pressuring Japan to remilitarise.

  • Decentralised the police and local government.

  • Strengthened the powers of Parliament and the Cabinet.

The Red Purge (1949–51)

After the Chinese Revolution of 1949 and the outbreak of the Korean War in 1950, the US had heightened concerns about the spread of communism in Asia. In 1949 Japan had also experienced ared scare, with industrial strikes and communists polling three million votes in the elections.

Worried that Japan might be at risk, the government and SCAP purged thousands of communists and leftists from government posts, teaching positions and private sector jobs. This act reversed some of the steps taken towards democracy in Japan and emphasised how important US Containment Policy was in running the country.

The Treaty of San Francisco (1951)

In 1951 defence treaties recognised Japan as being at the centre of a US defensive strategy. The Treaty of San Francisco ended the occupation of Japan and returned full sovereignty to the country. Japan was able to create a 75,000 strong army called the ‘self-defence force’.

The US retained influence in Japan via the American-Japanese Security Treaty, which enabled the US to retain military bases in the country.


The return of someone to their own country.

Red scare

Rising widespread fear of a potential rise from communism, which can be brought on by strikes or increased communist popularity.

The success of US Containment in Japan

US Containment Policy is often seen as a resounding success in Japan. Communism never had a chance to grow in the country due to the Japanese government and SCAP’s ‘reverse course’, which purged communist elements.

Japan’s economy also improved rapidly in the post-war years, removing conditions in which communism might take root. US policies in Japan also helped to establish Japan as a model capitalist country.

US Containment policy in China and Taiwan

After the Communists declared victory and established the People's Republic of China (PRC) in 1949, the Chinese Nationalist Party retreated to the island province of Taiwan and set up a government there.


An area of a country with its own government.

The Truman administration published the ‘China White Paper’ in 1949, which explained US foreign policy on China. The US was accused of having ‘lost’ China to communism. This was an embarrassment to America, which wanted to maintain a strong and powerful image, especially in the face of increasing Cold War tensions.

The US was determined to support the Nationalist Party and its independent government in Taiwan, which might have been able to re-establish control of the mainland.

The Korean War

China's support of North Korea in the Korean War demonstrated that China was no longer weak and was prepared to stand up to the West. Truman’s fears of the Korean conflict spreading to southern Asia then led to the US policy of protecting the Nationalist government in Taiwan.


Taiwan’s location also made it critically important. As a country backed by the West it served as a barrier to the Western Pacific, preventing Communist forces from reaching Indonesia and the Philippines. Taiwan was a key territory for containing communism and preventing China or North Korea from expanding any further.

The Taiwan Straits Crisis

During the Korean War, the US sent its Seventh Fleet into the Taiwan Strait to defend it against an invasion by the Chinese communists.

The Seventh Fleet

A numbered fleet (group of ships sailing together) of the US navy.

The US continued to build a strong alliance with Taiwan. The US lifted the US navy blockade of Taiwan and openly discussed signing a Mutual Defence Treaty with the Nationalist leader Chiang Kai-shek. Taiwan deployed troops to the islands. These actions were seen as a threat to the security of the PRC, which retaliated by attacking the island of Jinmen in 1954 and then Mazu and the Dachen Islands.

Concerned that the capture of these islands might delegitimise the Taiwanese government, the US signed the Mutual Defence Treaty with Taiwan. This did not commit to defending the offshore islands but promised support if a broader conflict with the PRC occurred.

US Containment Map of Taiwan and the Taiwan Strait StudySmarterMap of Taiwan and the Taiwan Strait, Wikimedia Commons.

The ‘Formosa Resolution’

In late 1954 and early 1955, the situation in the Strait deteriorated. This prompted the US Congress to pass the ‘Formosa Resolution’, which gave President Eisenhower the authority to defend Taiwan and the off-shore islands.

In Spring 1955, the US threatened a nuclear attack on China. This threat forced the PRC to negotiate and they agreed to stop the attacks if Nationalists withdrew from the Dachen Island. The threat of nuclear retaliation prevented another crisis in the strait in 1958.

US Containment policy success in China and Taiwan

The US was unsuccessful in containing communism in mainland China. Military and financial support for the Nationalist party during the civil war had proved fruitless. However, containment was a major success in Taiwan.

Chiang Kai-shek’s system of one-party rule crushed any opposition and did not allow for any communist parties to grow.

The rapid economic redevelopment of Taiwan was referred to as ‘the Taiwan Miracle’. It prevented communism from emerging and, like Japan, made Taiwan a ‘model state’, which demonstrated the virtues of capitalism.

However, without US military assistance, containment would have failed in Taiwan. The US’s nuclear capabilities were the main threat to the PRC, preventing it from engaging in full-blown conflict with the Nationalists in Taiwan, who were not strong enough to defend themselves.

Was US Containment policy successful in Asia?

Containment was successful in Asia to a certain extent. During the Korean War and the Taiwan Strait Crisis, the US managed to contain communism to North Korea and Mainland China. The US also managed to create strong ‘model states’ out of Japan and Taiwan, which encouraged other states to embrace capitalism.

Vietnam, Cambodia, and Laos

Containment policies in Vietnam, Cambodia and Laos were less successful and resulted in a deadly war that led many American (and global) citizens to question the US foreign policy of containment.

Vietnam and the Vietnam War

Vietnam had previously been a French colony, as part of Indochina and gained independence from France in 1945. The US pursued a policy of containment in Vietnam after the country was split into communist North Vietnam, governed by the Viet Minh, and South Vietnam. North Vietnam wanted to unite the country under communism and the US intervened to try and prevent this from happening. The war was long, deadly and became increasingly unpopular. In the end, the drawn-out and costly war resulted in millions of deaths and resulted in a communist takeover of the whole of Vietnam after American troops left in 1975. This rendered the US containment policy unsuccessful, as they had not prevented communism from spreading throughout Vietnam.

Laos and Cambodia

Laos and Cambodia, also previously under French rule both became caught up in the Vietnam War. Laos engaged in a civil war where the communist Pathet Lao fought against the US-backed royal government to establish communism in Laos. Despite US involvement, the Pathet Lao successfully took over the country in 1975. Cambodia also engaged in a civil war after a military coup ousted the monarch, Prince Norodom Sihanouk, in 1970. The communist Khmer Rouge fought with the deposed leader against the right-leaning military, and won in 1975.

All three countries, despite America's attempts to prevent communism from spreading, had become communist-ruled by 1975.

US Policy of Containment - Key takeaways

  • The US Policy of Containment in Asia focused on preventing the spread of communism rather than intervening in countries that were already communist-ruled.
  • The Truman Doctrine stated that the US would provide military and economic assistance to states threatened by communism.
  • The US made Japan into a satellite nation so that it could maintain a strong presence in Asia.
  • The US used economic aid to support anti-communist armies and rebuild countries devastated by war.
  • The US maintained a strong military presence in Asia and created a defence treaty to ensure states were defended against communist aggression.
  • The South-East Asian Treaty Organisation (SEATO) was similar to NATO and offered states mutual protection against communist threats.
  • The Chinese revolution and the Korean War made the US fear communist expansionism in the continent and accelerated containment policies.
  • US Containment Policy was successful in Japan, which benefited from economic aid and a military presence. It became a model capitalist state and a model for others to emulate.
  • After years of civil war, the Chinese Communist Party gained control over mainland China and founded the People’s Republic of China in 1949.
  • The Nationalist party retreated to Taiwan, where they set up an independent government, supported by the US.
  • During the Taiwan Straits crisis, mainland China and Taiwan fought over the islands in the straits. The US intervened, creating a defence treaty to protect Taiwan.
  • US Containment was very successful in Japan, South Korea and Taiwan. However, in Vietnam, Laos and Cambodia it was a failure.


1. The National Museum of New Orleans, ‘Research Starters: Worldwide Deaths in World War II’. https://www.nationalww2museum.org/students-teachers/student-resources/research-starters/research-starters-worldwide-deaths-world-war

Frequently Asked Questions about US Policy of Containment

US containment policy is the idea of containing and stopping the spread of communism. Rather than intervening in countries that were already communist-ruled, the US tried to protect non-communist countries that were vulnerable to invasion or communist ideology. 

The US contained communism in Korea by intervening in the Korean War and preventing South Korea from becoming a communist state. They also created the South East Asian Treaty Organisation (SEATO), a defence treaty with South Korea as a member state.  

The US Containment Policy is most often associated with the Truman Doctrine of 1947. President Harry S. Truman established that the US would provide ‘political, military and economic assistance to all democratic nations under threat from external or internal authoritarian forces’. This assertion then characterised the USA’s policy for much of the Cold War and led to US involvement in several overseas conflicts.

The US adopted a policy of containment as they feared the spread of communism. Rollback, a former policy that revolved around the US intervening to try and turn communist states back to capitalist ones had proved unsuccessful. Hence, a policy of containment was agreed upon.

The US contained communism by creating mutual defence treaties to ensure states protected each other, injecting financial aid into countries with struggling economies and to prevent the conditions that might lead to communism thriving, and ensuring a strong military presence on the continent.

Test your knowledge with multiple choice flashcards

Which of the following were strategies used to implement US Containment in Asia? (Choose two answers)

Which of these countries signed the South East Asian Treaty Organisation? (Choose two answers)

Which of these events led the US to feel a policy of Containment was necessary for Asia? (Choose two)


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