Imperialism and Foreign Policy: America as a World Power

Grade 11 · Social Studies · Study Guide

Examine how the United States emerged as an imperial power at the turn of the 20th century, the debates imperialism sparked, and the foreign policy doctrines that shaped America's global role.

By the 1890s, the United States had completed the conquest of its continental frontier and began looking outward. Driven by a combination of economic ambitions (new markets and investment opportunities), strategic considerations (naval power and coaling stations), cultural assumptions (Social Darwinism and the belief in Anglo-Saxon civilization's superiority), and religious impulses (spreading Christianity), the US joined European powers in imperial expansion. Alfred Thayer Mahan's influential book The Influence of Sea Power upon History (1890) argued that national greatness required a powerful navy, overseas bases, and merchant shipping lanes — ideas that directly shaped Theodore Roosevelt and other expansionists.

The Spanish-American War of 1898 was the decisive turning point. Cuba's rebellion against Spanish colonial rule generated US sympathy, and the mysterious explosion of the USS Maine in Havana Harbor on February 15, 1898 — blamed on Spain by a sensationalist yellow press led by William Randolph Hearst — provided the emotional spark. Congress declared war in April. The war lasted only 10 weeks: Spain was defeated in both Cuba and the Philippines. The Treaty of Paris (1898) gave the US Guam, Puerto Rico, and the Philippines (for $20 million). Cuba gained nominal independence but under tight US control through the Platt Amendment, which gave the US the right to intervene in Cuban affairs.

The acquisition of the Philippines triggered intense debate. Anti-imperialists — including Mark Twain, Andrew Carnegie, and former president Grover Cleveland — argued that colonial rule violated American founding principles of self-determination and democratic consent. Imperialists countered that the US had a duty to civilize and Christianize less developed peoples (Senator Albert Beveridge famously called it 'the divine mission of America'). Filipino resistance, led by Emilio Aguinaldo, turned into a brutal guerrilla war that lasted until 1902 and killed approximately 200,000–600,000 Filipinos and 4,200 American troops.

President Theodore Roosevelt's foreign policy was captured in his famous adage: 'Speak softly and carry a big stick.' The Roosevelt Corollary (1904) extended the Monroe Doctrine by asserting the US right to intervene in Latin American nations that failed to maintain order or pay their debts — effectively making much of Latin America a US protectorate. The US built the Panama Canal (completed 1914), acquiring the Canal Zone through a conveniently timed Panamanian revolution from Colombia that TR quietly encouraged. President Taft's 'Dollar Diplomacy' used US financial power to extend influence, while Wilson's 'Moral Diplomacy' claimed to promote democracy — though Wilson intervened militarily in Mexico, Haiti, and the Dominican Republic more than any previous president.

Results of the Spanish-American War (1898)
Territory	Status After 1898
Cuba	Nominal independence; Platt Amendment gave US right to intervene; US naval base at Guantanamo Bay
Puerto Rico	US territory; Puerto Ricans became US citizens in 1917 (Jones Act)
Philippines	US colony; Filipino-American War 1899–1902; independence granted 1946
Guam	US territory; strategic Pacific naval base
Hawaii	Annexed separately 1898 (not part of SpAm War treaty); became a state 1959

Comparing US Foreign Policy Doctrines (1890–1920)
Doctrine/Policy	President	Core Idea
Monroe Doctrine (original)	Monroe (1823)	Western Hemisphere closed to new European colonization
Roosevelt Corollary	TR (1904)	US can intervene in Latin America to maintain order and collect debts
Dollar Diplomacy	Taft (1909–1913)	Use US economic power to extend influence and stability
Moral Diplomacy	Wilson (1913–1921)	Support democratic governments; oppose those that oppress their people — but intervened militarily more than either predecessor

Key terms

Yellow journalism: Sensationalist reporting by newspapers (Hearst, Pulitzer) that exaggerated Spanish atrocities and the USS Maine explosion to whip up public support for war with Spain.
Platt Amendment (1901): US-imposed condition on Cuban independence giving the US the right to intervene in Cuba and maintain a naval base (Guantanamo Bay); kept Cuba as a virtual US protectorate.
Roosevelt Corollary (1904): TR's extension of the Monroe Doctrine asserting the US right to intervene in Latin American nations unable to maintain order or pay debts; justified repeated US military interventions.
Panama Canal: US-built canal through the isthmus of Panama, completed 1914; shortened shipping routes dramatically; acquired through a TR-encouraged Panamanian revolution against Colombia.
Anti-Imperialist League: Organization (1898) opposing US colonialism in the Philippines; members included Mark Twain, Andrew Carnegie, and former President Cleveland.
Dollar Diplomacy: Taft's policy of using US financial investments and economic leverage to expand US influence in Latin America and Asia.
USS Maine: US battleship that exploded in Havana Harbor on February 15, 1898 (likely accidentally); blamed on Spain by yellow press and used to justify declaring war.
Social Darwinism: Misapplication of Darwin's evolutionary theory to human societies; used to justify imperial expansion as the 'strong' civilizing the 'weak.'

Practice questions

The Roosevelt Corollary extended the Monroe Doctrine by claiming the US right to:
1. Prevent European nations from settling in the Western Hemisphere
2. Intervene in Latin American nations that failed to maintain order or pay debts
3. Build naval bases in all Caribbean nations
4. Impose American democratic governments on Latin American countries
Show answer
Answer: Intervene in Latin American nations that failed to maintain order or pay debts
The Roosevelt Corollary, announced in TR's 1904 State of the Union, justified the US acting as 'international police power' in the Western Hemisphere — used to justify interventions in the Dominican Republic, Nicaragua, Haiti, and elsewhere.
The United States acquired the Philippines after the Spanish-American War without any significant opposition from Filipinos.
Show answer
Answer: false
After the US decided to keep the Philippines (despite Filipino expectations of independence), Emilio Aguinaldo led an armed resistance that lasted until 1902 and killed an estimated 200,000–600,000 Filipinos and 4,200 Americans.
Yellow journalism's role in the Spanish-American War was to:
1. Provide balanced reporting on Spanish colonial policies in Cuba
2. Sensationalize events to whip up public support for war with Spain
3. Document the Filipino guerrilla war for American readers
4. Expose corporate corruption in the war profiteering industry
Show answer
Answer: Sensationalize events to whip up public support for war with Spain
Hearst's New York Journal and Pulitzer's New York World ran exaggerated and sometimes fabricated stories about Spanish atrocities and attributed the Maine explosion to Spain, building the public pressure for war.
What were the main arguments of the Anti-Imperialist League against US annexation of the Philippines? Were any of these arguments hypocritical given who led the organization?
Show answer
Answer: The Anti-Imperialist League argued that ruling the Philippines without their consent violated the Declaration of Independence's principle that just government derives from the consent of the governed. They also argued colonialism would corrupt American democracy and require maintaining a large standing army. The hypocrisy: many white members (including Carnegie and Twain) also held racist views that Filipinos were racially inferior — their objection was as much about avoiding entanglement with 'inferior races' as principled anti-colonialism.
The debate exposed real contradictions in American democratic ideals and the racial assumptions underlying both imperial and anti-imperial positions.
The Platt Amendment (1901) was controversial because it:
1. Required Cuba to pay Spain reparations after the war
2. Gave the US the right to intervene in Cuban affairs, undermining Cuban sovereignty
3. Forced Cuba to join the United States as a territory
4. Required Cuba to allow US corporations to own all its natural resources
Show answer
Answer: Gave the US the right to intervene in Cuban affairs, undermining Cuban sovereignty
The Platt Amendment was attached to the Cuban constitution as a condition of US military withdrawal; it gave the US the right to intervene to preserve Cuban independence or maintain a government adequate to protecting life and property — used to justify multiple interventions.

Fun facts

When asked what caused the USS Maine explosion, the Naval Court of Inquiry of 1898 blamed an external mine — but a 1974 US Navy investigation concluded the explosion was almost certainly an internal accident from spontaneous combustion in a coal bunker. The war was fought largely over an accident.
The Panama Canal required moving 268 million cubic yards of earth — enough to fill the Empire State Building 175 times. More than 5,600 workers died during US construction (1904–1914), mostly from yellow fever and malaria, following 22,000 deaths during the earlier failed French attempt.
Emilio Aguinaldo, who led Philippine resistance against Spanish rule and expected US support for independence, had actually been transported back to the Philippines on a US Navy ship before the Spanish-American War began — under the impression the US would recognize Filipino independence if Spain was defeated. He was betrayed.

Get a personalized course on Imperialism and Foreign Policy built around your child.