A long term result of the Monroe Doctrine was that the United States.

The Monroe Doctrine had a long lasting impact on the foreign policy of the United States. Presidents throughout history invoked the Monroe Doctrine when intervening in foreign affairs in the Western Hemisphere. Here are some examples of the Monroe Doctrine in action.
1865 - The U.S. government helped to overthrow Mexican Emperor Maximilian I who was put in power by the French. He was replaced by President Benito Juarez.
1904 - President Theodore Roosevelt added the "Roosevelt Corollary" to the Monroe Doctrine. He used the doctrine to stop what he called "wrongdoing" in several countries. It was the beginning of the U.S. acting as an international police force in the Americas.
1962 - President John F. Kennedy invoked the Monroe Doctrine during the Cuban Missile Crisis. The U.S. placed a naval quarantine around Cuba to prevent the Soviet Union from installing ballistic missiles on the island.
1982 - President Reagan invoked the Monroe Doctrine to fight communism in the Americas including countries such as Nicaragua and El Salvador.

The growth of the empire continued to increase their confidence.