The British Royal Navy—not the US military—enforced the Monroe Doctrine for most of the 19th century

The Monroe Doctrine was designed to keep Europe out of the Americas

First articulated in 1823 by President James Monroe, the doctrine declared the Western Hemisphere off limits to European colonization. It has since been invoked to justify US military interventions in Latin America, from Teddy Roosevelt's takeover of Venezuela to George H.W. Bush's arrest of Panama's leader Manuel Noriega.

A wave of Latin American independence movements most likely prompted the Monroe Doctrine

Between 1810 and 1822, many Latin American colonies separated from Spanish rule, 10 in the last two years. Concerns that Spain and its European allies might try to regain these republics were a main reason behind Monroe's declaration.

The Monroe Doctrine promoted 4 core principles

Monroe outlined four positions: the US would not interfere in European conflicts; it would not disturb existing European colonies in the Americas; the Western Hemisphere was closed to new colonization; and any European attempt to control an independent American republic would be regarded as a threat to US security.

The Monroe Doctrine helped lead to the American occupation of territory abroad

This podcast explores how the policy motivated a century of US military intervention throughout Latin America, the Caribbean, and the Pacific—covering the annexation of Hawaii, the Spanish-American War, and occupations of Cuba, Haiti, and Panama.

Hear about why Europe obeyed the Monroe Doctrine, despite American military weakness

This podcast explores the European background of the Monroe Doctrine, highlighting France's efforts to install aristocratic Bourbon monarchs in the newly independent Latin American republics—and how US opposition, British threats, and Spanish resistance ultimately disrupted those plans.

James Monroe first outlined what became known as the 'Monroe Doctrine' during his 1823 Annual Message to Congress

President Monroe used his Annual Message to Congress to warn European powers against further colonization in the Western Hemisphere, asserting US opposition to foreign intervention and laying the foundation for a cornerstone of American foreign policy that remains to this day.

Learn about the history of the Monroe Doctrine

CBS Sunday Morning explores the origins of the Monroe Doctrine, tracing how a 19th-century warning against European intervention shaped US foreign policy and influenced America’s role in the Western Hemisphere for generations.

The Roosevelt Corollary transformed the Monroe Doctrine from a defensive warning into a rationale for US military intervention

In 1904, President Theodore Roosevelt declared that the US had the right to exercise international police power in Latin America. Over the following two decades, the US intervened militarily in the region about a dozen times—often enough that Marines became known locally as "State Department troops."

Read an excerpt from the Monroe Doctrine, introduced in Monroe's 1823 address to Congress

On Dec. 2, 1823, President Monroe delivered his seventh annual message to Congress, now known as the State of the Union. One segment—warning European powers against interfering in the Western Hemisphere—became known as the Monroe Doctrine.

President Trump invoked the Monroe Doctrine in 2025, announcing a new 'Trump Corollary'

On Dec. 2, 2025, the 202nd anniversary of the doctrine, President Donald Trump issued a proclamation reaffirming US "dominance" in the Western Hemisphere. His administration's national security strategy officially codified the "Trump Corollary," stating that the US would prevent non-hemispheric powers from gaining strategic influence in the Americas.

The intellectual architect of the Monroe Doctrine was Secretary of State John Quincy Adams, not Monroe

Adams, the main foreign relations authority in the Cabinet, shaped the key parts of the Monroe Doctrine speech. He advocated for a unilateral American declaration to warn European powers, rejecting a potential joint statement with Britain favored by some Cabinet members.

France, Spain, and Britain formed a joint military alliance to force Mexico to repay its debts

In October 1861, the three powers signed the Convention of London and landed troops at Veracruz that December. Britain and Spain reached settlements with Mexico and withdrew. France refused and aimed to change the regime in power in Mexico.

Hear the reasoning behind Trump's resurrection of the Monroe Doctrine in 2025.

Near the end of the 1700s, the United States was forced to pay Barbary pirates an annual tribute equal to 16% of its entire budget.

Foreign policy and war defined Madison's presidency

During James Madison's presidency, disputes with Britain and France over trade, maritime rights, and impressment dominated foreign policy, culminating in the War of 1812 and shaping how the United States engaged with major European powers.

FDR's Good Neighbor policy reversed the interventionism that had grown from the Monroe Doctrine

Franklin Roosevelt pledged in his 1933 inaugural address to be a "good neighbor" to Latin America and to oppose armed intervention by American forces. His administration withdrew troops from previous occupations and signed a multilateral agreement stating that no state has the right to interfere in another's affairs.

Before Pearl Harbor, the US was a nonbelligerent ally to the Allied powers

Between September 1940 and December 7, 1941, the United States remained officially neutral—yet President Roosevelt incrementally shifted policy from “cash‑and‑carry” to Lend‑Lease, funneling critical military aid to Britain and other allies without entering the war.

European powers largely dismissed Monroe's declaration initially

The reaction in Europe ranged from quiet acceptance in Britain to outrage from Austria's Prince Metternich, who privately called it a "new act of revolt." At home, US newspapers reported a "warm and universal burst of applause," and Congress responded positively to the address.

The US intervened in Latin America to block communist influence during the Cold War

Fearing Soviet expansion, the US intervened across Latin America by backing coups, funding right-wing regimes, and supporting anti-communist militias—most notably in Cuba, Chile, Nicaragua and Guatemala.

The Barbary Wars were an early test of whether a president could wage war without a formal declaration from Congress

Jefferson sent naval forces against North African pirates without a congressional declaration of war, acting under his own authority. Years later, Madison took the opposite approach and formally sought congressional authorization.

Manifest destiny fueled US aggression against Mexico

The belief that the United States had a divine right to expand westward—known as manifest destiny—justified President Polk’s push for territorial conquest. It shaped public support for the Mexican-American War and framed the invasion as national destiny.

Jefferson feared European control in the West of North America

Jefferson pushed for the Louisiana Purchase to prevent France or Spain from dominating the western frontier, securing control of the Mississippi River and vast lands that he felt were essential to America’s strategic and economic future.

British colonialism left economic institutions that still shape growth today

This analysis argues that while the British Empire inflicted exploitation and long-term harm, it also exported institutions—like standardized property rights and land surveying—that boosted economic development in some colonies.

The Panama Canal boosted the US as a world power in trade, engineering, and finance

The effort proved the US could achieve grand engineering projects while granting it influence over (and benefitting economically from) a major interoceanic channel and its host country, Panama.

Before World War II, the US was a Pacific power

Decades before Pearl Harbor, the US held major Pacific territories—Hawaii, the Philippines, Guam, American Samoa, and numerous island bases—giving it strategic reach across the western Pacific. This presence increasingly overlapped with Japan’s imperial ambitions in the region, contributing to rising tensions.

American presidents did not travel abroad until Teddy Roosevelt visited the Panama Canal in 1906.

The Declaration of Independence was not only a statement of principles but also an appeal for military allies that the struggling colonists needed to survive.

Pontiac's Rebellion prompted Britain to draw a line between colonists and Native lands in 1763

After the French and Indian War, a coalition of Indigenous nations—led by Odawa leader Pontiac—launched a major uprising against British forts. In response, Britain issued the Royal Proclamation of 1763, which reserved lands west of the Appalachian Mountains for Native peoples.

In his 1859 annual message to Congress, President Buchanan articulated a narrow view of presidential military authority

Buchanan argued that the president lacked constitutional authority to launch offensive military action without congressional approval, a view that reflected the prevailing interpretation of executive war powers throughout much of the nineteenth century.

British rule in India wasn’t deliberate—it developed from trade

This academic explainer shows how Britain’s rule in India evolved from unplanned trading footholds to complete imperial control. It examines the decline of the Mughal Empire, economic expansion, racism, rebellion, and the mixed legacy of institutions and exploitation that still shape India today.

The US Board on Geographic Names is responsible for ensuring uniform usage of geographic names within the government.

US–Cuba contentious relations began long before the Cold War

Long before the revolution and missile crisis, US involvement in Cuba stretched back over 150 years—rooted in slavery, sugar, and shifting imperial ambitions. This short video traces how cycles of intervention and neglect shaped the island’s modern history.

How the US took half of Mexico

In just two years, the United States redrew the map of North America. Sparked by border disputes in Texas and fueled by President James Polk’s drive for expansion, the Mexican–American War (1846–1848) reshaped both nations.

Alexander Hamilton argued in Federalist 69 that the president's military authority was far more limited than a king's

Hamilton wrote that the president's commander-in-chief role amounted to little more than the authority to command the military, while the powers to declare war, raise armies, and regulate fleets belonged to the legislature. He contrasted this with the British king to argue that the executive posed no threat of tyranny.

A small island nation built the largest empire in history

See how Britain grew from a small kingdom into a global empire ruling nearly a third of the world, then unraveled through war, nationalist movements, and declining power—leaving just 14 overseas territories as remnants of its once-vast domain.

The history of deep-sea mining and its governance by the International Seabed Authority

The British HMS Challenger research vessel identified metal-rich seafloor rocks between Hawaii and Mexico in the 1870s, but rules governing which nations control which parts of the ocean were not established until 1958 by the UN. It later established the ISA to oversee mineral-related operations in international waters.

France invaded Mexico to install a puppet monarchy and recover debt

Napoleon III used Mexico's default on foreign loans as cover for a larger imperial ambition: overthrowing President Benito Juárez's government and installing a French-backed monarchy. The Mexican army's surprise victory at Puebla helped delay those plans by nearly a year.

The US handed control of the canal back to Panama in 1999

This was the result of two treaties signed during President Jimmy Carter's presidency, one shifting control to Panama and the other declaring the canal zone neutral. In recent years, US officials have suggested the US may retake control. Experts agree that the only viable way would be through military force.

The Truman Doctrine marked the start of US containment strategy

Introduced in 1947, the Truman Doctrine pledged US support for nations resisting communism—starting with Greece and Turkey—and launched the containment policy that defined early Cold War strategy.

Mexico’s political chaos weakened its defense against US invasion

Mexico’s post-independence instability—marked by coups, power struggles, and weak central control—left its northern frontier vulnerable. That political fragmentation shaped Mexico’s unpreparedness during the Mexican-American War and helped enable US conquest.

The framers feared creating another monarchy through an unchecked executive

Having rebelled against British royal power, the framers deliberately limited the presidency—balancing "energy in the executive" with safeguards against tyranny. Debate at the 1787 Constitutional Convention centered on preventing any return to monarchical rule.

Colonial Americans used tobacco, wampum, and land-backed notes to solve a chronic coin shortage

British coins rarely circulated in the colonies due to an unfavorable trade balance, forcing colonists to improvise. They traded in Spanish dollars, Native American shells, tobacco warehouse receipts, and eventually paper money backed by land rather than gold.

See how Britain promoted imperial trade through 1920s propaganda posters

This photo gallery showcases posters from the Empire Marketing Board, created after Canada gained dominion status in 1926. The campaign encouraged Canadians to buy goods from across the British Empire, producing more than 800 posters displayed nationwide.

Critics argued Hamilton prioritized central power over popular sovereignty

This podcast examines Hamilton's belief in expansive federal power and why he was repeatedly labeled a monarchist—tracing how his calls for a strong executive, his life-tenure proposals at the Constitutional Convention, and his admiration for British stability fueled accusations that he favored centralized power over republican rule.

Colonial self-rule fostered strong autonomy and distrust of centralized power

American colonies were governed through a patchwork of different systems, ranging from Crown-run to locally controlled. Broad local autonomy—often followed by sudden imperial crackdowns—taught colonial leaders to prize home rule and distrust distant centralized power, attitudes that later informed US federalism.

Some colonies were centuries-old before they broke from Britain

The revolution did not happen overnight, but was a culmination of centuries of settlement, policies, and war in North America. This timeline provides key, fascinating events from the 1600s through the Revolution in a smooth, easy-to-read interface.

Opposition to British taxes, regulation of trade was key to American independence

The economic situation in the colonies formed the backbone of the central events of the Revolution. British war debts caused it to lay the first direct taxes on colonists, cease their westward expansion claims, and adhere to stringent trade regulations, leading to backlash and eventual separation.

The US used military pressure to force Japan to open to foreign trade in the 1850s

Commodore Matthew Perry arrived in Edo Bay (now Tokyo Bay) with heavily armed warships, pressuring Japan to open its ports. His expeditions led to the 1854 Treaty of Kanagawa, which opened two ports for supplies and established formal US-Japan relations. Full commercial trade followed later under the 1858 Harris Treaty.

Watch the British Empire expand and recede over 5 centuries

This interactive map traces the British Empire from 1450 to today—showing its explosive 19th-century expansion to one-quarter of the world's land and its steady contraction after World War II.

Some historians claim that Mexico's victory at Puebla may have prevented France from arming the Confederacy

According to some experts, Napoleon III planned to ship weapons from Mexico to Confederate forces to break the Union naval blockade. The delay caused by the Battle of Puebla meant French resources didn't reach the Texas border until after the Union Army's decisive victory at Vicksburg.