One of the central pillars of U.S. President Donald Trump’s new national security strategy is a plan to update a more than 200-year-old foreign policy statement known as the Monroe Doctrine.
“After years of neglect, the United States will reassert and enforce the Monroe Doctrine to restore American preeminence in the Western Hemisphere, and to protect our homeland and our access to key geographies throughout the region,” the strategy document unveiled last week states.
The document goes on to lay out a “‘Trump Corollary’ to the Monroe Doctrine” that prioritizes American-led cooperative efforts to combat mass migration, drug trafficking and “hostile foreign incursion or ownership of key assets.”
The strategy marks the latest evolution of the Monroe Doctrine, which has been held up as either an argument for peace and non-intervention or justification for American imperialism — depending on how U.S. presidents interpreted it.
The implications of the doctrine were particularly felt in Latin America, where Trump is currently seeking an array of strategies — from military action near Venezuela to financial aid for Argentina — to exert U.S. influence.
Here’s what to know about the Monroe Doctrine and how it has evolved over the years.
What is the Monroe Doctrine?
U.S. President James Monroe delivered what became known as the Monroe Doctrine during a State of the Union address to Congress in 1823.
The text, developed by his secretary of state John Quincy Adams, asserted that countries in the western hemisphere — identified as North and South American continents — “are henceforth not to be considered as subjects for future colonization by any European powers.”
At the time, Latin American nations were establishing their independence from Spain, and they welcomed Monroe’s statement as affirming their freedoms.
Yet Monroe also made clear he wanted to see the United States as the new dominant power over the hemisphere, by asserting later in the speech that any “inter-dispositions” by “any European power” would be viewed as a threat to American “peace and safety.”
Get daily National news
Get the day’s top news, political, economic, and current affairs headlines, delivered to your inbox once a day.
This portion of Monroe’s speech would not be formalized as the Monroe Doctrine until the late 1800s, by which time the U.S. had established itself as a world power capable of exerting its influence through military might. That’s when it began to be viewed as a key tenet of U.S. foreign policy.
In 1904, U.S. President Theodore Roosevelt issued what became known as the “Roosevelt Corollary” to the Monroe Doctrine, which envisioned the U.S. as “an international police power” that would keep western hemisphere nations “stable, orderly and prosperous.”
Roosevelt had issued his corollary to ensure the U.S., not Europe, would intervene if necessary and “however reluctantly” to keep Latin American countries financially solvent.
Yet it was later used to justify multiple U.S. military interventions and occupations in Central American and Caribbean nations in the early 20th century, in what historians have called “gunboat diplomacy” and the so-called Banana Wars.
At the same time, Canadian politicians including then-prime minister Wilfrid Laurier were suggesting the Monroe Doctrine would protect Canada from foreign invasion because the U.S. would come to its defence.
How did the Doctrine evolve further?
U.S. President Franklin D. Roosevelt effectively ended the Latin American interventions with the Good Neighbor policy of 1934, which sought to re-establish diplomacy and economic cooperation in the region.
However, the Cold War saw the end of that approach and re-emergence of the Monroe Doctrine as a basis for countering communism and Soviet expansionism in the western hemisphere.
That, in turn, led to a series of U.S.-backed regime change operations in Central and South America, including the 1954 coup in Guatemala that had covert support from the CIA. The doctrine was also used to justify U.S. support for right-wing dictatorships like the Pinochet regime in Chile.
In 1962, U.S. President John F. Kennedy directly cited the Monroe Doctrine in a press conference to explain why the U.S. was seeking to “isolate the communist menace in Cuba” — culminating in the Cuban Missile Crisis that year.
The Monroe Doctrine was also invoked by then-CIA director Robert Gates when it emerged that the U.S., with funds from secret arms sales to Iran, was training guerilla soldiers to overthrow the Sandinista socialist government in Nicaragua, in what became known as the Iran-Contra affair.
In 2013, then-U.S. secretary of state John Kerry declared during a speech to the Organization of American States that “the era of the Monroe Doctrine is over,” which was seen as another shift toward warming relations with Latin America.
Yet Kerry also warned during this time that the U.S. must continue to pay attention to what is happening in America’s “backyard.”
Why does Trump want to bring it back?
Trump seeking to “reassert and enforce the Monroe Doctrine” is further evidence of his “America First” approach to foreign policy, experts and members of his administration say.
“Past administrations perpetuated the belief that the Monroe Doctrine had expired. They were wrong,” U.S. Defense Secretary Pete Hegseth said in a speech on Saturday.
“The Monroe Doctrine is in effect and it is stronger than ever under the Trump Corollary, a common sense restoration of our power and prerogatives in this hemisphere consistent with U.S. interests.”
That strategy has been most visible in U.S. military strikes on suspected drug boats in the Caribbean Sea since September, which have killed nearly 90 people so far, as well as a U.S. military buildup near Venezuela.
Max Cameron, a political science professor at the University of British Columbia who studies Latin America, told Global News those operations had created “a sense of horror in many places that this is a return to gunboat diplomacy, to the Monroe Doctrine, to the Americans treating the Caribbean as an American lake that they can control and do what they want in.”
Others have noted Trump’s recent announcement of a US$20-billion bailout for Argentina, and his support for the country’s right-wing populist President Javier Milei, as another sign of the Monroe Doctrine at work.
Alejandro Garcia Magos, a political science lecturer at the University of Toronto, said the alliance of “ideological soulmates” Trump and Milei may counterbalance the regional influence of more leftist leaders like Brazilian President Luiz Inácio Lula da Silva.
“It’s an opportunity for Trump to have a solid friend and ally in a region that in the last 25 years has been difficult for the American to have a solid footing in,” he told Global News.
© 2025 Global News, a division of Corus Entertainment Inc.
