American Isolationism

Isolationism was the foundation of America's foreign policy for much of the nineteenth century. It was characterised by American reluctance to get involved in the messy sphere of European politics and wars. But throughout the twentieth century, the America's policy of isolationism was constantly tested. By the end of the Second World War, the United States had all but abandoned American isolationism.

American Isolationism American Isolationism

Create learning materials about American Isolationism with our free learning app!

  • Instand access to millions of learning materials
  • Flashcards, notes, mock-exams and more
  • Everything you need to ace your exams
Create a free account
Table of contents

    American Isolationism Definition

    Isolationism is a policy where a country decides to not engage in the affairs of other nations. In practice, this involves a reluctance to enter into international agreements, including alliances, treaties, and trade deals. The origins of isolationism date back to the colonial period. Having been denied self-determination by European nations, it is easy to understand why America wanted to avoid involvement with these same nations when they were independent.

    Although they formed an alliance with France during the American War of Independence (1775–83), this was quickly dissolved in 1793 by George Washington, who argued that:

    The duty and interest of the United States require that they [the United States] should with sincerity and good faith adopt and pursue a conduct friendly and impartial towards the belligerent Powers."

    - President George Washington, Neutrality Proclamation, 17931

    American Isolationism Portrait of George Washington, the first President of the United States StudySmarterFig. 1 - Portrait of George Washington, the first President of the United States (30 April 1789 - 4 March 1797)

    This impartiality was further consolidated in 1801 by President Thomas Jefferson, who said America should seek:

    [P]eace, commerce, and honest friendship with all nations, entangling alliances with none…"

    - President Thomas Jefferson, Inaugural Address, 18012

    American Isolationism Thomas Jefferson, the third President of the United States StudySmarterFig. 2 - Thomas Jefferson, the third President of the United States (4 March 1801 - 4 March 1809)

    American Isolationism Pros and Cons

    Isolationism's main pro is that it enables a nation to devote all its efforts to its internal affairs. The cons of isolationism emerged as the US industrialised and found itself drawn into international events.

    Examples of American Isolationism

    The Monroe Doctrine was an example of American isolationism enunciated by President James Monroe in 1823. It stated the Old World and New World should be separate spheres of influence as they were fundamentally different.

    The Old World was used to refer to Europe. The New World referred to the Americas and its 'discovery' in the late fifteenth century.

    This meant that the US would not interfere in the internal affairs of European nations or involve themselves in European conflicts. Whilst it recognised existing colonies and dependencies in the Western Hemisphere, it announced that the Americas were closed to future European colonisation.

    This did not, however, prevent the US from interfering in the affairs of nations in the Western Hemisphere. What started as protecting the Americas from European interference evolved into intervening in central and South American countries for the United States’ own interests.

    American Isolationism Threats Nineteenth Century

    Isolationism had broad support throughout the early nineteenth century but certain threats to isolationism soon emerged. For one, the US was undergoing industrialisation, which meant it needed foreign markets and raw materials, necessitating increased foreign involvement. The US began producing steamships, undersea communication cables, and radio, which decreased the impact of geographical isolation by linking America with other countries.

    World events also challenged the policy of isolationism. After the 1898 Spanish–American War, the US bought the Philippines from Spain. War broke out in the Philippines and America occupied the country for almost 50 years. Expansionists supported these events but for isolationists, it was a severe blow to their ideology.

    The occupation of the Philippines was especially significant considering it was generally regarded to be in Japan’s sphere of influence. Japan's military-industrial empire was growing at this point, as was that of Germany, which would come to further threaten American isolationism as these nations became increasingly aggressive.

    American Isolationism First World War

    President Woodrow Wilson was re-elected in 1916 on the basis that he had kept America out of the War. However, in April 1917 the US entered the War after Germany resumed submarine warfare on US ships. Wilson made the case that entering the War served the country's interests by maintaining peaceful world order and that the US should make the world ‘safe for democracy.’ He argued that this was supporting and applying the Monroe Doctrine to the world, saying ‘no nation should seek to extend its polity over any other nation or people.’

    American Isolationism Woodrow Wilson, the 28th President of the United States StudySmarterFig. 3 - Woodrow Wilson, the 28th President of the United States (4 March 1913 - 4 March 1921)

    After being involved in a war that originated in Europe, the US policy of isolationism was abandoned. During the war, the US entered into binding alliances with Britain, France, Russia, Italy, Belgium, and Serbia. President Wilson’s Fourteen Points speech in 1918 expressed principles for world peace, which were key in peace negotiations at the end of the War. However, despite the heavy involvement of the US, they returned to a policy of isolationism immediately after the First World War.

    American isolationism after the First World War

    American isolationism after the First World War started by with ending all US commitments in Europe as soon as the war ended. The casualties which the US experienced during the War further supported returning to isolationism.

    Significantly, the US Senate rejected the 1919 Treaty of Versailles, which was drawn up to end the War and dismantle the German empire. The Treaty established the League of Nations, which was proposed in Wilson’s Fourteen Points. Precisely on this basis, that the US would have to join the League of Nations, the Senate rejected the Treaty and entered into separate peace treaties. The group of senators who opposed the treaty are known as the Irreconcilables.

    Although they did not join the League of Nations, the US took some steps in foreign policy with the same goals as the League, including disarmament, preventing war, and protecting peace. Notable events included:

    • The Dawes Plan of 1924, which provided a loan to Germany to pay their reparations to Britain and France, who would then pay off their US loans with the money.

    • The Young Plan in 1929 reduced the overall amount of reparations Germany had to pay.

    • The Kellogg-Briand Pact of 1928 outlawed war as foreign policy and was signed by the US, France and 12 other nations.

    • The Japanese invasion of Manchuria led to the Stimson Doctrine, which stated that the US would not recognise any territory gained by aggression and against international agreements.

    In terms of domestic policy, the end of the First World War led to high tariffs on foreign goods in order to protect American businesses from foreign competition. Immigration was curbed with the introduction of Immigration Acts.

    While the US did not completely return to isolationism, it focused on internal affairs. It only engaged in foreign affairs to limit the chance of another war, with the notable exception of the Dawes and the Young Plans.

    American Isolationism Second World War

    The Great Depression of 1929–39 saw a renewed commitment to isolationism. President Franklin Roosevelt (1933-45) put this into practice by introducing the Good Neighbour Policy in Latin America, which promoted hemispheric cooperation and led to a decline in US interference with other nations in the Americas.

    American Isolationism Portrait of Franklin D Roosevelt, the 32nd President of the United States StudySmarterFig. 4 - Portrait of Franklin D Roosevelt, the 32nd President of the United States (4 March 1933 - 12 April 1945)

    Despite this, President Roosevelt generally favoured a more active role for the US in international affairs. Attempts to act on this were however prevented by Congress which was heavily isolationist. In 1933, for example, Roosevelt proposed granting him the right to coordinate with other countries to put pressure on aggressive nations, but this was blocked.

    American Isolationism Second World War The Neutrality Acts

    With the rise of Nazi Germany, Congress passed a series of Neutrality Acts to prohibit US involvement in the war. Roosevelt opposed these restrictive Acts, but he conceded in order to maintain support for his domestic policies.

    1935 First Neutrality Act Prohibited the US from exporting military equipment to warring foreign nations. This was renewed in 1936, and also prohibited the US from offering loans to warring nations.
    1937 Neutrality ActFurthered these restrictions by forbidding US merchant ships to transport arms produced outside the US to warring foreign nations. The Spanish Civil War, which began in 1936, led to the explicit forbidding of weapons involvement. This Act did however introduce the ‘cash-and-carry’ provision, which allowed the US to sell non-military items to warring nations, provided that the goods were paid for immediately and transported on non-American ships.
    1939 Third Neutrality ActLifted the arms embargo, including military equipment in the ‘cash-and-carry’ provision. Providing loans and transporting goods on American ships were still banned.

    American Isolationism Second World War America First Committee

    After the outbreak of the Second World War in 1939, aviator Charles A. Lindbergh formed the America First Committee (AFC) in 1940. This specifically aimed to keep the US out of the war. It was a popular organisation, with a membership that grew to over 800,000.

    Lindbergh articulated the premise of the organisation as:

    An independent American destiny means, on the one hand, that our soldiers will not have to fight everybody in the world who prefers some other system of life to ours. On the other hand, it means that we will fight anybody and everybody who attempts to interfere with our hemisphere."

    - Charles A. Lindbergh, Rally Speech in New York, 19413

    This isolationist group also opposed the Lend-lease plan introduced in 1941 by Roosevelt, which provided military aid to countries whose defence was integral to US security. Most of Congress supported this idea, but isolationists such as those in the American First Committee remained staunchly opposed.

    The organisation was however short-lived as public opinion began to favour intervention in the War. Japan's attack on Pearl Harbour in 1941 brought the US into the war and solidified public support. The America First Committee was disbanded. Lindbergh himself became supportive of their efforts during the War.

    End of American Isolationism

    The US entry into the Second World War signalled the end of its policy of isolationism. Throughout the War, the US was part of the Grand Alliance with Britain and the Soviet Union, which coordinated the War effort and began to plan post-War action.

    After the War ended, the US helped to establish the United Nations in 1945 and became a charter member of the organisation, abandoning their previous aversion to such international cooperation. Policies such as the Truman Doctrine (1947) which promised US intervention to protect countries from communist takeover, and the Marshall Plan (1948) which gave aid to rebuild Europe after the War, saw an important role for the US in international relations post-Second World War.

    The emergence of the Cold War came to be the most important factor for the US foreign policy in the years that followed. Foreign policy was now based on preventing the spread of communism –a policy known as US Containment – as opposed to isolationism.

    American Isolationism - Key Takeaways

    • Isolationism was the attitude that the US took in their foreign policy throughout the nineteenth and into the twentieth century. It was particularly popular after the losses the US experienced during the First World War.
    • Threats to isolationism emerged in the mid-nineteenth century when the US began to industrialise, increasingly communicating with other nations.
    • Even when the US did enter into agreements after the First World War, these were generally motivated to reduce the chance of another war through policies such as disarmament.
    • Presidents Woodrow Wilson and Franklin Roosevelt favoured a larger role for the US in international relations, but Congress was overwhelmingly isolationist and opposed proposals such as entering the League of Nations.
    • Entry into the Second World War signalled the end of US isolationism. The US took a large role in post-war Europe and became involved in the Cold War.


    1. George Washington, Neutrality Proclamation, 1793. You can read it online at:
    2. Thomas Jefferson, Inaugural Address, 1801. You can read it online at:
    3. Charles A. Lindbergh, 'Election Promises Should Be Kept We Lack Leadership That Places America First', Madison Square Garden, New York Rally, 1941.
    4. Fig. 4 - Portrait of Franklin D Roosevelt ( by FDR Presidential Library & Museum ( Licensed by CC BY 2.0 (
    Frequently Asked Questions about American Isolationism

    What was American isolationism?

    American isolationism refers to the US policy of not getting involved in the affairs of other nations, particularly through avoiding entering into international agreements.

    What historical factors contributed to American isolationism?

    American isolationism originated from the US colonisation. Having been denied self-determination by European nations, it is easy to understand why America wanted to avoid involvement with these same nations when they were independent.

    When did the US stop isolationism?

    The policy of American isolationism ended after the US entered the Second World War, during and after which it entered international alliances and helped to rebuild Europe.

    Did American isolationism cause the First World War?

    No. American isolationism did not cause the War. But US entry into it did greatly assist in ending the War as they provided significant support.

    How did American isolationism cause the Second World War?

    It didn't. However, American isolationism contributed to the War in that the US did not use its vast power to prevent authoritarianism from spreading across the world.

    Test your knowledge with multiple choice flashcards

    When did President James Monroe introduce what came to be known as the Monroe Doctrine?

    The Roosevelt Corollary ______ the Monroe Doctrine.

    The Good Neighbour Policy aimed to _______ relations with countries in the Western Hemisphere.


    Discover learning materials with the free StudySmarter app

    Sign up for free
    About StudySmarter

    StudySmarter is a globally recognized educational technology company, offering a holistic learning platform designed for students of all ages and educational levels. Our platform provides learning support for a wide range of subjects, including STEM, Social Sciences, and Languages and also helps students to successfully master various tests and exams worldwide, such as GCSE, A Level, SAT, ACT, Abitur, and more. We offer an extensive library of learning materials, including interactive flashcards, comprehensive textbook solutions, and detailed explanations. The cutting-edge technology and tools we provide help students create their own learning materials. StudySmarter’s content is not only expert-verified but also regularly updated to ensure accuracy and relevance.

    Learn more
    StudySmarter Editorial Team

    Team History Teachers

    • 11 minutes reading time
    • Checked by StudySmarter Editorial Team
    Save Explanation

    Study anywhere. Anytime.Across all devices.

    Sign-up for free

    Sign up to highlight and take notes. It’s 100% free.

    Join over 22 million students in learning with our StudySmarter App

    The first learning app that truly has everything you need to ace your exams in one place

    • Flashcards & Quizzes
    • AI Study Assistant
    • Study Planner
    • Mock-Exams
    • Smart Note-Taking
    Join over 22 million students in learning with our StudySmarter App

    Get unlimited access with a free StudySmarter account.

    • Instant access to millions of learning materials.
    • Flashcards, notes, mock-exams, AI tools and more.
    • Everything you need to ace your exams.
    Second Popup Banner