Unit 6: American Imperialism & World War I (1890-1920)

Imperialism 

Imperialism is the policy of extending a nation’s power through territorial acquisition or by exerting political or economic control over other nations. In the late 19th and early 20th centuries, the U.S. pursued imperialism by acquiring overseas territories and expanding its influence. This era marked a shift from isolationism to global engagement.

Rev. Josiah Strong

A Protestant clergyman, Strong advocated for Anglo-Saxon superiority and believed it was America’s duty to spread Christianity and Western values. His ideas reflected Social Gospel ideals mixed with imperialist justifications. He influenced support for U.S. expansionism.

Alfred Mahan

A naval officer and historian, Mahan argued in The Influence of Sea Power upon History that national greatness depended on naval supremacy. His work influenced U.S. policy, leading to the expansion of the navy and overseas bases. He was a key intellectual behind American imperialism.

The Great Rapprochement

This term describes the growing diplomatic closeness between the U.S. and Great Britain in the late 19th century. Shared cultural ties and mutual interests led to improved relations, especially as tensions eased over border disputes. It laid the groundwork for future alliances.

Queen Liliuokalani

The last monarch of Hawaii, Queen Liliuokalani resisted U.S. annexation and attempted to restore native Hawaiian control. She was overthrown by American planters with U.S. military backing in 1893. Her removal paved the way for Hawaii’s eventual annexation.

Annexation of Hawaii

The U.S. annexed Hawaii in 1898 after American planters, supported by U.S. forces, overthrew Queen Liliuokalani. The islands were strategically important for military and economic reasons, particularly during the Spanish-American War. Hawaii became a U.S. territory in 1900.

Yellow Journalism

Sensationalist and exaggerated reporting by newspapers like those of Hearst and Pulitzer helped stir American public support for war with Spain in 1898. Stories often included lurid tales of Spanish atrocities, especially in Cuba. This style of journalism played a role in pushing the U.S. into the Spanish-American War.

de Lôme Letter

A private letter from the Spanish ambassador de Lôme criticized President McKinley as weak. Its publication in U.S. newspapers outraged the public and increased anti-Spanish sentiment. It contributed to the growing momentum toward war with Spain.

The USS Maine

An American battleship that exploded in Havana Harbor in 1898, killing over 260 sailors. Although the cause was unclear, the press blamed Spain, fueling cries for war. “Remember the Maine!” became a rallying cry leading into the Spanish-American War.

William McKinley

As president during the Spanish-American War, McKinley supported U.S. intervention in Cuba and later oversaw the annexation of the Philippines, Guam, and Puerto Rico. His administration marked a turning point toward U.S. imperialism. He was re-elected in 1900 but assassinated in 1901.

Teller Amendment

Passed by Congress in 1898, this amendment declared that the U.S. would not annex Cuba after winning the Spanish-American War. It aimed to reassure anti-imperialists and justify intervention as liberating rather than conquering. However, later actions contradicted this promise.

Spanish-American War

Fought in 1898, the war began over Cuban independence but quickly expanded into a broader conflict. The U.S. defeated Spain and gained control of Guam, Puerto Rico, and the Philippines. It marked America’s emergence as an imperial power.

Rough Riders

A volunteer cavalry regiment led by Theodore Roosevelt during the Spanish-American War. They became famous for their charge up San Juan Hill in Cuba. Their exploits helped Roosevelt gain national fame.

Anti-Imperialist League

Formed in 1898, this group opposed U.S. expansion into overseas territories, especially the Philippines. Members included Mark Twain, Andrew Carnegie, and former President Cleveland. They argued imperialism contradicted American democratic ideals.

White Man’s Burden

A concept popularized by Rudyard Kipling’s poem, it encouraged imperial powers like the U.S. and Britain to “civilize” non-Western peoples. It reflected racist and paternalistic justifications for imperialism. Americans used this ideology to defend overseas expansion.

Foraker Act

Passed in 1900, this act established civilian government in Puerto Rico under U.S. control. It allowed some local self-governance but denied full rights and citizenship to Puerto Ricans initially. It demonstrated how the U.S. managed its new territories.

Insular SCOTUS Cases

These Supreme Court decisions ruled that U.S. constitutional rights did not fully apply to new territories. They created a distinction between “incorporated” and “unincorporated” territories. These rulings justified limited rights for colonial subjects.

Platt Amendment

Inserted into the Cuban Constitution in 1901, it allowed the U.S. to intervene in Cuban affairs and maintain a naval base at Guantanamo Bay. It limited Cuban sovereignty despite formal independence. It reflected U.S. dominance in the Caribbean.

Emilio Aguinaldo

A Filipino revolutionary leader who initially supported U.S. efforts against Spain, but later fought against American occupation of the Philippines. He led the Filipino Rebellion from 1899 to 1902. His resistance challenged U.S. imperial policy.

Filipino Rebellion

After the U.S. annexed the Philippines, Filipino nationalists led by Aguinaldo launched a brutal insurgency from 1899–1902. The conflict resulted in heavy casualties and widespread atrocities. It revealed the darker side of American imperialism.

Open Door Note/Policy

Proposed by Secretary of State John Hay in 1899, it advocated equal trade access to China for all imperial powers. It aimed to protect U.S. commercial interests without colonizing Chinese territory. It became a cornerstone of U.S. Asia policy.

Boxer Rebellion

A 1900 uprising in China led by a nationalist group (the “Boxers”) aimed to expel foreign influence. An international force, including the U.S., intervened to suppress the rebellion. It justified further foreign presence in China.

Panama Canal

Built between 1904 and 1914, the canal connected the Atlantic and Pacific Oceans through Central America. The U.S. supported Panama’s independence from Colombia to secure control of the canal zone. It was a major engineering feat and symbol of U.S. global power.

Big Stick Diplomacy

Theodore Roosevelt’s foreign policy mantra—“speak softly and carry a big stick”—emphasized negotiation backed by the threat of force. It was used to assert U.S. power in Latin America and globally. It led to interventions and canal building.

Roosevelt Corollary

An addition to the Monroe Doctrine, the Roosevelt Corollary declared that the U.S. could intervene in Latin American countries to stabilize them. It justified numerous U.S. actions in the Caribbean. It marked a more aggressive imperial stance.

Gentlemen’s Agreement with Japan

In 1907, Japan agreed to limit emigration to the U.S., while the U.S. would stop the formal exclusion of Japanese immigrants. The informal agreement was a response to racial tensions in California. It attempted to maintain diplomatic relations.

Great White Fleet

A fleet of U.S. Navy ships sent around the world by Roosevelt from 1907–1909 to showcase American naval power. It was a diplomatic and military gesture to assert U.S. strength. The fleet stopped in Japan, Europe, and other nations.

Dollar Diplomacy

Coined during President Taft’s administration, Dollar Diplomacy encouraged U.S. investment abroad, especially in Latin America and East Asia, to promote American economic and political interests. The idea was to replace military intervention with financial influence. However, it often led to resentment and instability in the regions targeted.

Woodrow Wilson

Wilson was the 28th president of the United States, serving from 1913 to 1921. He promoted progressive reforms domestically and pursued an idealistic foreign policy rooted in moral diplomacy. Wilson led the U.S. through World War I and proposed the League of Nations, though the U.S. ultimately did not join it.

Jones Law of 1916

Also known as the Philippine Autonomy Act, this law pledged eventual independence for the Philippines and established a more autonomous Filipino legislature. It was a step toward self-government but kept ultimate authority in U.S. hands. It reflected growing American attempts to justify its imperial presence as benevolent.

Moral/Missionary Diplomacy

Woodrow Wilson’s foreign policy emphasized the promotion of democratic ideals and moral principles abroad. He rejected imperialism and sought to support nations with similar values, though in practice the U.S. still intervened in Latin America. The policy aimed to distinguish Wilson from his predecessors’ more aggressive approaches.

Pancho Villa

A Mexican revolutionary leader, Villa conducted raids into the U.S., including an attack on Columbus, New Mexico in 1916. In response, the U.S. launched a military expedition into Mexico to capture him, led by General Pershing, but failed. Villa became a symbol of instability in U.S.-Mexico relations.

Allied Powers

During World War I, the Allied Powers included countries like Britain, France, Russia, Italy, and later the United States. They fought against the Central Powers and were united largely by their opposition to German and Austro-Hungarian aggression. The alliance eventually triumphed in 1918.

Central Powers

This alliance in World War I included Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria. They opposed the Allied Powers and sought to expand or preserve their empires. The Central Powers were ultimately defeated in 1918, leading to major territorial and political losses.

The Lusitania

A British passenger ship sunk by a German U-boat in 1915, killing 1,198 people, including 128 Americans. The attack outraged the American public and increased tensions between the U.S. and Germany. While it did not immediately lead to war, it moved the U.S. closer to involvement in WWI.

Sussex Pledge

After Germany attacked the French ship Sussex in 1916, injuring Americans, it promised to stop unrestricted submarine warfare against non-military ships. This pledge temporarily eased tensions with the U.S. However, Germany later broke the pledge, contributing to U.S. entry into WWI.

Unrestricted Submarine Warfare

Germany resumed unrestricted submarine warfare in 1917, targeting all ships—military or civilian—around Allied waters without warning. This tactic aimed to cut off supplies to Britain but resulted in American deaths. It was a key factor in the U.S. decision to enter World War I.

Zimmermann Note

In 1917, British intelligence intercepted a message from Germany to Mexico proposing a military alliance if the U.S. entered the war. In return, Germany promised to help Mexico reclaim lost U.S. territory. The note angered Americans and pushed public opinion further toward war.

Wilson’s Fourteen Points

President Wilson’s 1918 plan for postwar peace emphasized self-determination, free trade, open diplomacy, and the creation of a League of Nations. The points reflected his idealism and vision for a more just international order. While not fully adopted, they influenced the Treaty of Versailles debates.

Committee on Public Information

Led by George Creel, this government agency used propaganda to rally public support for World War I. It produced posters, films, speeches, and articles to promote patriotism and demonize the enemy. The CPI played a major role in shaping public opinion during the war.

Espionage & Sedition Acts (1917–18)

These laws criminalized interference with the draft, support for enemies during wartime, or criticism of the U.S. government and military. They severely limited civil liberties, especially freedom of speech. Many socialists and antiwar activists were imprisoned under these acts.

Schenck v. United States

In this 1919 Supreme Court case, Charles Schenck was convicted for distributing anti-draft leaflets. The Court ruled his actions posed a “clear and present danger” and upheld limits on free speech during wartime. The decision set a precedent for restricting civil liberties during national emergencies.

War Industries Board

Created in 1917, this agency coordinated industrial production during WWI by setting quotas, allocating raw materials, and standardizing products. It increased efficiency and mobilized the economy for wartime needs under the leadership of Bernard Baruch.

National War Labor Board

Formed in 1918, this board mediated labor disputes to prevent strikes and ensure wartime production. It supported workers’ rights to unionize and pushed for better wages and hours, gaining labor’s cooperation during the war.

Great Migration

The Great Migration saw hundreds of thousands of African Americans move from the rural South to Northern cities between 1916 and 1970, especially during WWI. They sought better jobs and escape from segregation. This movement reshaped the demographics and culture of urban America.

Food Administration

Led by Herbert Hoover, the Food Administration encouraged voluntary conservation during WWI, promoting “Meatless Mondays” and “Wheatless Wednesdays.” It ensured food supplies for both civilians and soldiers without imposing strict rationing.

Victory Gardens

Americans were encouraged to grow their own vegetables at home to support the war effort. Victory Gardens helped reduce pressure on the public food supply and became a patriotic symbol of home-front contribution.

Liberty Loans

The U.S. government issued Liberty Bonds to raise funds for the war. Citizens were urged to buy bonds as a patriotic duty, and widespread participation helped finance the massive costs of WWI.

John “Black Jack” Pershing

General Pershing led the American Expeditionary Forces (AEF) in World War I. He insisted on maintaining a separate U.S. command and played a key role in major Allied offensives in 1918 that helped win the war.

Henry Cabot Lodge

A Republican senator and foreign policy expert, Lodge led opposition to the Treaty of Versailles and the League of Nations. He pushed for reservations to protect U.S. sovereignty. His resistance contributed to the treaty’s failure in the Senate.

Irreconcilables

This group of mostly Republican senators strongly opposed the Treaty of Versailles in any form, particularly the League of Nations. They feared it would entangle the U.S. in foreign conflicts and undermine congressional war powers.

Treaty of Versailles

Signed in 1919, the treaty officially ended WWI and imposed harsh penalties on Germany, including territorial losses, disarmament, and reparations. It also created the League of Nations. The U.S. Senate ultimately rejected it.

League of Nations

Proposed in Wilson’s Fourteen Points and established in the Treaty of Versailles, the League was intended to prevent future wars through collective security. The U.S. never joined due to Senate opposition, weakening its effectiveness.

Article X (Treaty of Versailles)

This controversial clause committed League members to defend each other’s sovereignty. Critics argued it could force the U.S. into unwanted wars without congressional approval. Opposition to Article X was a major reason the Senate rejected the treaty.

Isolationism

After World War I, many Americans favored a return to non-involvement in foreign affairs. Isolationism shaped U.S. policy in the 1920s and 1930s, contributing to the rejection of the League of Nations and a reluctance to enter future conflicts.

Jones-Shafroth Act (1917)

This act granted U.S. citizenship to residents of Puerto Rico and restructured the island’s government. It established a bicameral legislature and gave Puerto Ricans more control over local affairs, though ultimate authority still rested with the U.S. It marked a step toward greater political rights without full autonomy or statehood.

U.S. Railroad Administration

Created during World War I, the U.S. Railroad Administration temporarily nationalized the railroads from 1917 to 1920 to ensure efficient wartime transportation. It unified the system, set standardized rates, and prioritized troop and supply movement. After the war, control was returned to private companies.