America thought that the Monroe doctrine was important and on many occasions brought up in debates such as sending troops to Caribbean nations. What is the Monroe doctrine? The Monroe doctrine is a statement written by president James Monroe of central Americas. This statement said that the United States were not to interfere with the European nations affairs or existing European colonies. It also told that the United States were to not try and build colonies in the Americas. This message showed that the U.S was determined to keep European power out of the western hemisphere. However, the U.S didn't have the military power to enforce the Monroe Doctrine. Luckily, Britain agreed with the statement. With Britain having a powerful navy they were able to enforce the Monroe Doctrine. Monroe's statement helped shape the foreign policy of the U.S for 100's of years.