5.1 American Expansionism and the Spanish-American War

American expansionism in the late 19th century grew out of economic pressures, a belief in Manifest Destiny, and the rise of naval power. The Spanish-American War of 1898 became the turning point that transformed the United States from a continental nation into a colonial power with overseas territories, setting the stage for its role as a major global player in the 20th century.

American Expansionism in the Late 19th Century

Motivations for American Expansionism

Manifest Destiny had originally referred to the belief that the United States was destined to expand across North America. By the late 1800s, that idea was being applied beyond the continent to justify overseas expansion.

Several economic pressures pushed the country outward:

• American factories were producing more goods than the domestic market could absorb, creating a desire for new markets abroad
• Industries needed raw materials (rubber, sugar, minerals) that could be sourced from tropical regions
• Investors saw opportunities for profit in foreign lands, particularly in the Caribbean and the Pacific

The 1890 Census officially declared the American frontier closed, meaning there was no longer a clear line of unsettled territory stretching westward. This triggered real anxiety. Many leaders believed that without new frontiers to expand into, American economic growth would stall and the national character would weaken. Overseas expansion seemed like the logical next step.

Rise of American Naval Power and Overseas Expansion

Alfred Thayer Mahan, a naval officer and strategist, published The Influence of Sea Power upon History in 1890. His core argument was straightforward: great nations need strong navies, and strong navies need overseas bases and coaling stations to operate globally. Mahan's ideas caught on quickly with politicians like Theodore Roosevelt and Henry Cabot Lodge, who pushed for a naval buildup and the acquisition of strategic territories.

This thinking directly shaped the path toward the Spanish-American War of 1898, which resulted in the U.S. acquiring Puerto Rico, Guam, and the Philippines. The war marked a clear shift: the United States was no longer just a continental power but a nation with colonial possessions spread across the Caribbean and the Pacific.

The Spanish-American War

Causes of the Spanish-American War

Three factors combined to push the United States toward war with Spain:

Cuba's independence struggle began in 1895, and it drew strong American sympathy. Many Americans saw parallels between Cuba's fight against Spain and their own revolution against Britain. Beyond sentiment, American businesses had roughly $50 million invested in Cuban sugar plantations and other enterprises, and the ongoing conflict threatened those investments.

The sinking of the USS Maine on February 15, 1898, in Havana Harbor killed 266 American sailors. The actual cause of the explosion remains debated to this day, but at the time, the American press and public quickly blamed Spain. "Remember the Maine!" became a rallying cry for war.

Yellow journalism turned public opinion into a firestorm. Newspaper publishers William Randolph Hearst (New York Journal) and Joseph Pulitzer (New York World) competed for readers by printing sensationalized and sometimes outright fabricated stories about Spanish brutality in Cuba. These papers didn't cause the war on their own, but they made it politically very difficult for leaders to avoid one.

Key Events and Consequences of the War

The path from cause to consequence moved quickly:

1. Congress passed the Teller Amendment, which pledged that the U.S. would support Cuban independence and would not annex the island.
2. The United States declared war on Spain on April 25, 1898.
3. On May 1, Commodore George Dewey destroyed the Spanish fleet at the Battle of Manila Bay in the Philippines, a swift victory that stunned the world.
4. In Cuba, American forces fought the Battles of El Caney and San Juan Hill in July 1898. Theodore Roosevelt and his volunteer cavalry unit, the Rough Riders, gained national fame during the San Juan Hill assault, though regular Army regiments (including African American Buffalo Soldiers) did much of the fighting.
5. Spain sued for peace, and the Treaty of Paris was signed on December 10, 1898.

Under the Treaty of Paris:

• Spain ceded Puerto Rico, Guam, and the Philippines to the United States (the U.S. paid Spain $20 million for the Philippines)
• Cuba gained formal independence, though it remained heavily under American influence
• The United States emerged as a colonial power for the first time

The entire war lasted only about four months, but its consequences reshaped American foreign policy for decades.

Impact of the Spanish-American War on American Power

Shift in American Foreign Policy

The war forced a national debate about what kind of country the United States wanted to be. Imperialists, including Roosevelt and Senator Albert Beveridge, argued that the U.S. had a duty to spread democracy and civilization, and that holding overseas territories was necessary for economic and strategic strength.

Anti-imperialists, including Mark Twain, Andrew Carnegie, and the Anti-Imperialist League, pushed back hard. They argued that ruling foreign peoples without their consent violated the principles of the Declaration of Independence and the Constitution. The Senate ratified the Treaty of Paris by just one vote more than the required two-thirds majority, showing how divided the country was.

Increased American Influence in the Caribbean and Latin America

The war's aftermath gave the U.S. a dominant position in the Caribbean:

• The Platt Amendment (1901) gave the United States the right to intervene in Cuban affairs and required Cuba to lease land for an American naval base at Guantanamo Bay. Cuba was technically independent, but the Platt Amendment made it clear who held the real power.
• The Roosevelt Corollary to the Monroe Doctrine (1904) went further, declaring that the U.S. could intervene anywhere in Latin America to maintain stability and prevent European interference. This policy justified repeated American interventions in the region for years to come.
• The construction of the Panama Canal (1904–1914) expanded American strategic reach by connecting the Atlantic and Pacific oceans, making it far easier to move naval and commercial ships between the two.

Global Power Dynamics and Colonial Territories

The Spanish-American War put the United States on a collision course with other imperial powers. Germany in particular viewed American expansion in the Pacific and Caribbean as a threat to its own colonial ambitions, and tensions between the two nations simmered in the years that followed.

The acquired territories each followed a different path:

• Puerto Rico became an unincorporated territory of the United States. Its residents were granted U.S. citizenship in 1917 but did not have full representation in Congress or the right to vote in presidential elections.
• The Philippines resisted American rule almost immediately. The Philippine-American War (1899–1902) was a brutal conflict that cost over 200,000 Filipino civilian lives and roughly 4,200 American soldiers. It exposed the contradiction of a republic fighting to suppress another people's independence.
• Guam became a strategically important American naval base in the western Pacific, a role it continues to play today.