Roosevelt said that the United States would prevent Latin American countries from illegal actions.
After World War I, Latin American countries were newly formed with the United States. For establishing its base in South America, US guaranteed independence all the newly formed countries.However vast resources and developed manpower combined with the growing strength of the United States.
This strength helped in preventing from all the illegal operations in newly formed Latin American. Therefore in the newly formed Latin America countries, the United States signifies as a "police officer" during President Theodore Roosevelt's reign.