Imperialism and the First World War

History of the USA · The modern United States. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.

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The idea

In 1898 the United States became an overseas power. The short Spanish-American War, fought over Cuba, ended with the United States holding Puerto Rico, Guam and the Philippines. Hawaii was annexed the same year. In China, where it held no sphere of influence, it asked for an Open Door: equal trade for all nations.

In the Caribbean it claimed the right to intervene, through the Platt Amendment in Cuba and the Roosevelt Corollary, and it built the Panama Canal.

The United States stayed neutral in the First World War until 1917. German submarine attacks and the Zimmermann Telegram brought it in. Wilson offered the Fourteen Points as a basis for peace, but the Senate refused the Treaty of Versailles and the League of Nations.

Rules to remember

USS Maine exploded in Havana harbour, February 1898; war with Spain the same year.
Treaty of Paris 1898: Cuba independent; Puerto Rico and Guam ceded; Philippines sold for $20 million.
Open Door notes 1899 to 1900, Secretary of State John Hay.
Platt Amendment 1901: United States could intervene in Cuba and hold a naval base (Guantánamo Bay).
Roosevelt Corollary 1904: the United States would act as policeman in Latin America. Panama Canal opened 1914.
Lusitania sunk 1915; unrestricted submarine warfare and the Zimmermann Telegram, early 1917; war declared April 1917.
Fourteen Points, January 1918; Senate rejected the Treaty of Versailles, 1919 to 1920 (Henry Cabot Lodge).

Common mistake

The sinking of the Lusitania (1915) did not bring the United States into the war. It entered two years later, in April 1917, after Germany resumed unrestricted submarine warfare.

Worked example

How did the Roosevelt Corollary change the meaning of the Monroe Doctrine?

The Monroe Doctrine (1823) was defensive: it told European powers to keep out of the Americas.
The Corollary (1904) said that if a Latin American state fell into disorder or could not pay its debts, the United States itself would step in.
So a warning to Europe became a claim to a right of intervention by the United States.

Answer: It turned a doctrine against European intervention into a justification for American intervention in Latin America.

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