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

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.

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.

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 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.

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

In the early to mid-1800s, the US lacked the ships and military power to prevent European nations from colonizing the Americas. Britain enforced this to protect its commercial interests by keeping rival European powers out of Latin America.

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.

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.

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.

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."

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

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.

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 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.

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.

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.

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

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.

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.

The Soviet Union had a similar sphere of influence policy during the Cold War—the Brezhnev Doctrine

Articulated in 1968, the Brezhnev Doctrine claimed the Soviet Union's right to intervene militarily in its satellite states to prevent any deviation from communist rule. It was used to justify the invasion of Czechoslovakia that same year and the invasion of Afghanistan in 1979.

Much of the Global South responded to the Russia-Ukraine war by pursuing a strategy of 'active nonalignment'

Boston University scholar Jorge Heine suggests that countries across Africa, Asia, and Latin America are avoiding taking sides between Washington and Beijing—viewing the rules-based order as increasingly unresponsive to the needs of developing nations and considering the West's framing of the war irrelevant to its own interests.

The Kennan Telegram shaped early US Cold War strategy

In 1946, diplomat George Kennan sent a long telegram from Moscow warning that the Soviet Union was inherently expansionist. His analysis laid the groundwork for the US policy of containment that defined the early Cold War.

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.

The diplomat who implemented Monroe's policy introduced the poinsettia to the United States

Joel Roberts Poinsett, appointed as the first US minister to Mexico in 1825 following the doctrine's announcement, took cuttings of a vibrant Mexican plant called the cuetlaxochitl during his time there. Americans loved the foliage and named it after him.

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 US embargo on Cuba was designed to cause hardship and eventual regime change

A secret 1960 memo by State Department official Lester Mallory argued that trade restrictions were “the only foreseeable means” to unseat Castro by provoking hunger and desperation. This page compiles declassified US documents detailing that strategy and its aftermath.

The world rapidly decolonized after World War II, with roughly a hundred new countries emerging between 1945 and 1989.

Decolonization isn't complete, as nearly 2 million people were living in UN-designated non-self-governing territories as of 2023.

The Marshall Plan aimed to rebuild Europe and limit Soviet influence

Launched in 1948, the Marshall Plan provided over $12B (roughly $150B today) in US aid to help rebuild Western Europe. While framed as economic recovery, it also served as a Cold War tool—tying countries to the US and excluding the Soviet bloc.

In the 1930s, Congress nearly passed a constitutional amendment requiring a national vote before declaring war

The Ludlow Amendment, proposed amid rising isolationism after World War I, would have required a national referendum before Congress could declare war, except in cases of direct attack. It was defeated 209 to 188 in 1938 after Roosevelt lobbied against it.

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.

John Marshall gained national prominence during the XYZ Affair

In 1797, President John Adams sent Marshall to France amid seizures of American ships. French intermediaries demanded loans and bribes before talks, and Marshall refused. Publication of the dispatches fueled the Quasi-War and elevated his reputation in the United States.

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.

President Polk deliberately provoked war with Mexico

After Mexico refused to sell California and New Mexico, President James K. Polk ordered US troops into disputed territory between the Nueces River and the Rio Grande—knowing it would likely spark a conflict. When fighting broke out, he used it to justify declaring war.

As president, Thomas Jefferson expanded federal power despite opposing centralized authority

Although Jefferson argued for limited national power, his presidency expanded federal authority through actions such as the Louisiana Purchase, territorial governance, and federal enforcement—reflecting a pragmatic departure from his earlier strict interpretation of the Constitution.

Madison urged Jefferson to accept the Louisiana Purchase despite constitutional concerns

As secretary of state, James Madison helped negotiate the 1803 Louisiana Purchase and persuaded Thomas Jefferson to proceed, arguing that the strategic and economic stakes outweighed the unresolved constitutional questions.

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.

Mexico admired Lincoln for opposing the war and supporting Mexican sovereignty

As a congressman, Abraham Lincoln condemned the Mexican-American War as unjust. Years later, as president, he backed Mexico’s fight against French occupation. His principled stance earned enduring respect and monuments across Mexico.

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.

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.

The Nationality Act of 1790 restricted new citizenship to 'free white persons'

The first federal citizenship law limited naturalization to white immigrants, excluding enslaved people, Indigenous communities, and most non-Europeans.

Post-WWII decolonization in Africa led to Cold War proxy conflicts

As newly independent African nations emerged after World War II, the US and USSR vied for influence—backing opposing sides in civil wars and revolutions. Conflicts in Angola, Ethiopia and Mozambique became proxy fronts in the Cold War.

Defining the use of 'Third World' in geopolitics

The term "Third World" is mostly out of use today for its limiting connotations, but in light of a reordering of geopolitical alliances amid the Ukraine war, historians are reevaluating the term's usefulness. Read the history of the term starting from the 1950s, and learn what several experts claim about its contemporary efficacy.

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.

Jefferson sent Lewis and Clark to map, trade, and secure the West

Beyond seeking a water route to the Pacific, Jefferson tasked the Corps of Discovery with mapping the new Louisiana Territory, cataloging its resources, and establishing trade with Native nations.

The Cuban Revolution, from 1953 to 1959, overthrew the dictatorship of Fulgencio Batista and established the first socialist state in the Western Hemisphere.

The colonial origins of Haiti/Dominican Republic divide

This 16-minute video explores the colonial origins of the modern-day split between Haiti and the Dominican Republic. Haiti previously was the French-Caribbean colony of Saint-Domingue, which was torn off the Spanish colony of Santo Domingo in 1697....

Future President Abraham Lincoln challenged Polk’s justification for war with Mexico

As a freshman congressman, Abraham Lincoln introduced the “Spot Resolutions,” demanding President Polk prove that Mexico had attacked on US soil. This constituted Lincoln’s first major political stand and highlighted growing dissent over the war.

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.