Final answer:
Theodore Roosevelt's commitment to the 'big stick' policy was most clearly demonstrated in his interventionist actions in Latin American affairs, aligning with his view to use American power to enforce the Monroe Doctrine to prevent European influence in the region.
Step-by-step explanation:
President Theodore Roosevelt's foreign policy, famously summarized by the proverb "Speak softly and carry a big stick; you will go far," is most clearly demonstrated by the way he intervened in Latin American affairs. Roosevelt extended the Monroe Doctrine with what became known as the Roosevelt Corollary, which posited the United States as an "international police power." He aimed to prevent European intervention in the Western Hemisphere by asserting the right to intervene in Latin American countries to maintain order and collect debts. Roosevelt's approach backed his military and diplomatic actions in the Caribbean.
Although Roosevelt had a significant impact on conservation and domestic policies—such as the Square Deal which included consumer protection, corporate regulations, and environmental conservation—his acknowledgment of the "big stick policy" is not as directly related to those endeavors as it is to his actions in the international sphere, specifically regarding Latin America.