The Roosevelt Corollary was set forth by President Theodore Roosevelt in 1904 (in his State of the Union Address that year). It was a tweaking of the Monroe Doctrine. The Monroe Doctrine expressed US opposition to European interference in the Americas. Roosevelt's corollary to that doctrine was that the United States would intervene in conflicts between European countries and Latin American countries, rather than having the Europeans press their claims directly.
The policy became known as the "Big Stick" policy because Roosevelt used the policy to put the United States in the position of primary power broker in the Western Hemisphere, so that the USA would have the upper hand in Latin American affairs.
The phrase came to be automatically associated with Roosevelt and was frequently used by the press, especially in cartoons, to refer particularly to his foreign policy; in Latin America and the Caribbean, he enacted the Big Stick policy (in foreign policy, also known as the Roosevelt Corollary to the Monroe Doctrine). If you need something different, please let me know. Hope I helped.
