In 1823, President James Monroe’s seventh annual message to congress said that “the American continents, by the free and independent condition which they have assumed and maintain, are henceforth not the considered as subjects of future colonization’s by any European powers…”¹ This is known today as the Monroe Doctrine. 

The function of the Monroe Doctrine could be distilled down to a handful of major efforts.  First, the United States did not want to grant European competitors a beachhead to be able to launch attacks or stage a power competition.  Second, it was a diplomatic warning shot as the colonial interests and wealth of Spain, Portugal, England, Russia and France were all put on notice that they could be confronted as a matter of United States Foreign Policy.  This engagement would be primarily be sea.  The Monroe Doctrine would function as an executive police action to engage foreign meddling in the hemisphere rather than requiring a discrete declaration of war by congress.  

Monroe and John Quincy Adams are the architects.  They were 11 years past the start of the War of 1812. They understood that trans-oceanic wars were easy to protract and expensive for the expeditionary country. Like Armies marching on Moscow during the winter. There is a tyranny of distance in the logistical supply of sustainment of the force.  Territory is hard to keep at a distance.  

The United States holds an inherent advantage due to their proximity to the other countries in the Western Hemisphere with the shorter distances to overcome. This strategy proved effective because it kept the European powers at bay and depressed the other governments in the western hemisphere.  These under-developed countries were ripe exploitation as the U.S. looked to wield its own influence, deny territory to adversaries and capture the surrounding natural resources for their own national enrichment.   

In 1904, President Theodore Roosevelt added the Roosevelt Corollary which established Big Stick Diplomacy.  

“Chronic wrongdoing, may…ultimately require intervention by some civilized nation, and in the Western Hemisphere the adherence of the United States to the Monroe Doctrine may force the United States…to the exercise of an international police power.”²  

Here, Roosevelt converts the old defensive minded doctrine into an offensive foreign policy that authorized American interference in the internal affairs of Western countries if they were not maintaining “civility” per the standards of that day’s U.S. President. This became known as “Gun Boat Diplomacy” because if a country stepped out of line a U.S. Navy Gunboat would land in their port and explain to them how to behave or lose their city 

Future leaders walked back the Roosevelt Corollary with Presidents Hoover and Franklin Roosevelt implementing the “Good Neighbor Policy” which sought to foster more reciprocal trade with other Latin American countries.³  However, as the Cold War ramped up, this approach was scrapped in favor of a more proactive policy for fighting Communism in the Western Hemisphere such as the Cuban Missile Crisis.  Thus, the United States returned to the elder Roosevelt’s strategy of 70 years before and practiced that until the fall of the USSR in 1991.  

The function, development and history of the Monroe Doctrine have pragmatically aided the United States staying the strongest economic and maritime power in the western hemisphere for nearly 200 years.