In 1823, U.S. President James Monroe announced that European powers should no longer attempt to colonize or install puppet regimes in any part of North or South America. In 1904, President Theodore Roosevelt expanded on those principles in what became known as the Roosevelt Corollary to the Monroe Doctrine. Following Roosevelt's more aggressive stance in world affairs, the Corollary asserted the U.S. had the right to intervene in South and Central American affairs as necessary to protect its interests.
Hemisphere of Influence
The Monroe Doctrine was the U.S. response to European efforts to maintain strongholds in Latin America through various interventions in the political and economic systems of former colonies. The Doctrine was invoked in 1865 as the basis for U.S. diplomacy and military support of Mexican President Benito Juárez's campaign to overthrow the country's France-installed dictator.
Expansion of Power
In 1902, Great Britain, Germany and Italy used military ships to block Venezuelan ports to pressure the country to repay its debts. This crisis led President Roosevelt to embellish the Monroe Doctrine, claiming the right to use U.S. military forces to repel European incursions in Latin America. The Roosevelt Corollary expanded the Doctrine's focus from passive prevention to active intervention.
Further military intervention in the region led to a period of intense confrontation between the U.S. forces and people living in Central America and the Caribbean. Over time the Corollary became less about the relationship between Europe and Latin American countries and more a justification for the U.S. to use unilateral military force to influence politics and economics throughout the Western Hemisphere. U.S. forces were deployed in Cuba, Nicaragua, Haiti and the Dominican Republic to quell internal strife and protests. Increasing U.S. intervention brought criticism from many Latin American leaders who didn't believe the U.S. had the right to invade or manage other countries without an invitation.
Taking a Short Cut
The construction of the Panama Canal were an example of how far the Roosevelt Corollary extended. President Roosevelt believed a canal through the isthmus of Central America, connecting the Atlantic and Pacific Oceans, was essential to U.S. military and economic interests. Panama seemed the best location, but it was a province of Colombia. U.S. attempts to form a treaty with Colombia that would allow it to build and defend the canal fell apart. Leaning on the principles of the Roosevelt Corollary, the U.S. military forces in the area prevented Colombia from stopping a Panamanian revolution. When Panama had gained its independence, the U.S. brokered a deal with the French company that owned the rights to build the canal – not the newly-installed Panamanian leaders. The deal gave the U.S. complete political and military control of the territory where the canal was built.