Before 1880, the United States focused mostly on settling its own continent — pushing west, fighting Native American nations, and building railroads. By the 1890s that frontier was declared closed, and American leaders started looking outward instead. This shift from a continental power to a global one is what the IB calls expansionist foreign policy. It didn't happen for one reason — it was political, economic, social, and ideological reasons working together.
- Political reasons — leaders like President William McKinley and, later, Theodore Roosevelt believed a strong nation needed an overseas presence to be taken seriously by European empires such as Britain and Germany
- Economic reasons — American factories and farms were producing more than the home market could buy; businessmen wanted new markets to sell to and new places (Cuba, the Philippines, Latin America) to invest in and get raw materials from
- Social reasons — a wave of nativism and racial thinking made many Americans believe it was their duty to 'civilize' other peoples
- Ideological reasons — the idea of Manifest Destiny (America's destiny to spread its influence) was extended from the continent to the whole hemisphere and beyond
The Mahan influence: Naval officer Alfred Thayer Mahan argued in The Influence of Sea Power upon History (1890) that great nations need a strong navy, overseas coaling stations, and colonies to fuel and supply their ships. His ideas convinced US leaders to build a modern battleship navy and look for island bases — a direct cause of the push into the Caribbean and the Pacific.
Put simply: the US had the industrial muscle of a great power by 1890, and its leaders decided it should start acting like one. That decision is the background to everything else in this topic — the Spanish-American War and the assertive policies (Big Stick, Dollar Diplomacy, Moral Diplomacy) that followed it.
Command word alert: Questions on this section often use 'To what extent' or 'Examine the reasons for'. Always separate the FOUR reason-types (political / economic / social / ideological) into distinct paragraphs — examiners reward a structured, categorised answer over a single blended narrative.
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By the 1890s, Spain still ruled Cuba, right next to the United States, and Cubans were fighting a brutal war of independence against Spanish rule. This gave the US both a moral excuse and a strategic opportunity to expand — and the result was the Spanish-American War of 1898, a short conflict that changed America's role in the world almost overnight.
Cuban unrest
Cuban rebels fought Spain for independence from 1895. Spanish General Valeriano Weyler herded civilians into brutal reconcentration camps, and thousands died of disease and starvation.
Yellow press
US newspapers owned by Joseph Pulitzer and William Randolph Hearst exaggerated Spanish cruelty in sensational ('yellow') journalism, stirring American public sympathy for the Cuban rebels.
USS Maine explodes
In February 1898 the US battleship Maine exploded in Havana harbour, killing 266 sailors. The cause was probably an internal accident, but the American press blamed Spain, and 'Remember the Maine!' became a rallying cry.
War declared
Congress declared war on Spain in April 1898. Fighting lasted only a few months and the US won quickly, helped by its navy — proving Mahan's theory that sea power meant global power.
Rebels resist, papers provoke, Maine explodes, war follows fast.
| Effect | What changed |
|---|---|
| Cuba | Became formally independent, but the Platt Amendment (1901) forced Cuba to let the US intervene militarily and lease Guantánamo Bay — independence in name only |
| Puerto Rico | Ceded to the US and became an American territory |
| Guam | Ceded to the US, giving America a Pacific naval base |
| The Philippines | Bought from Spain for $20 million under the Treaty of Paris (1898) — but Filipino rebels under Emilio Aguinaldo then fought a bloody war against US rule until 1902 |
| US global status | The US now controlled overseas colonies for the first time — it had become an imperial power, not just a continental one |
The debate at home: Not everyone supported this. The Anti-Imperialist League (which included figures like Mark Twain) argued that ruling other peoples without their consent betrayed America's own founding ideals of liberty and self-government. This tension — expansion versus American ideals — is a useful point for essays that ask you to evaluate US foreign policy.
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After 1898, three US presidents each developed their own style of asserting American power over Latin America and the Caribbean. Each policy used a different main tool — the same underlying goal (US dominance and stability favourable to American interests) came in three different packages.
1. The Big Stick (Theodore Roosevelt, 1901–1909)
Roosevelt's approach was based on his saying: 'speak softly and carry a big stick.' It meant backing diplomacy with the threat — and occasional use — of military force.
- Panama Canal (1903) — when Colombia refused a canal treaty, Roosevelt supported a Panamanian revolt against Colombia, then quickly recognised the new nation and secured rights to build the canal, completed in 1914
- Roosevelt Corollary (1904) — an addition to the Monroe Doctrine, claiming the US had the right to intervene in Latin American nations' affairs to keep European powers out and 'stabilize' the region
- Interventions — US Marines were sent into Caribbean and Central American states (e.g. the Dominican Republic) under this claimed right
2. Dollar Diplomacy (William Howard Taft, 1909–1913)
Taft preferred economic pressure over the military. Dollar Diplomacy meant encouraging US banks and companies to invest in Latin American economies (railways, sugar, mining), so that American money — not just American guns — controlled the region. If a country got into debt trouble, the US often stepped in to protect the investment, which could still mean sending Marines (as happened in Nicaragua in 1912).
3. Moral Diplomacy (Woodrow Wilson, 1913–1921)
Wilson criticised both earlier approaches as selfish. His Moral Diplomacy claimed the US would only support governments that were just and democratic, refusing to recognise regimes that took power by force. In practice, though, Wilson still used military intervention — notably occupying Haiti (1915) and sending troops into Mexico (the 1916 Pershing Expedition, chasing Pancho Villa) — so critics say his 'moral' policy looked a lot like the Big Stick in a different name.
What changed between the three
- Roosevelt: force first
- Taft: money first
- Wilson: 'principle' first — claimed to reject force
What stayed the same
- All three intervened militarily in Latin America when it suited US interests
- All three assumed the US had the right to direct the region
- All three protected US economic interests
Essay-ready comparison: A strong Paper 3 answer doesn't just describe the three policies — it argues that despite different rhetoric (force / money / morality), all three delivered the same outcome: US hemispheric dominance. That continuity-under-different-labels is exactly the kind of analytical point examiners reward.