The correct answer is:
Law enforcer of the Western Hemisphere was the role of the United States as envisioned by the Roosevelt Corollary to the Monroe Doctrine.
The Roosevelt Corollary, consistent with his Big Stick Diplomacy, was written in 1904 after the Venezuela Crisis of 1902–03, as an addition to the Monroe Doctrine.
It stated that the US would intervene in conflicts between European and Latin American countries to enforce legitimate European claims, instead of having them pressing their claims directly.