Final answer:
Theodore Roosevelt believed that the United States had a duty to expand its values to foreign peoples, confirmed through the Roosevelt Corollary that expanded the Monroe Doctrine.
Step-by-step explanation:
The individual who stated that the United States has a duty to spread its values to foreign peoples is Theodore Roosevelt. In his tenure as President, Roosevelt expanded upon the Monroe Doctrine through his foreign policy, which became known as the Roosevelt Corollary. He articulated the United States' right and obligation to act as an international police power, using military force if necessary, to ensure stability in the Western Hemisphere. This approach was justified by the view that spreading the boundaries of the United States was equivalent to spreading freedom, and it was seen as a moral imperative that could instill American men with resolve and vigor.