12. What reason did President Roosevelt give that the United States was responsible for policing the Western Hemisphere? A. European nations were too isolationist to interfere in other countries' affairs. B. U.S. doctrine prevented other nations from intervening in the Americas C. Latin America had asked the U.S. to be an internationa police power.

## Step 1<br />This problem is a multiple-choice question related to U.S. history, specifically the presidency of Franklin D. Roosevelt. The question asks for the reason that Roosevelt gave for the United States' responsibility in policing the Western Hemisphere.<br /><br />## Step 2<br />The options provided are:<br />A. European nations were too isolationist to interfere in other countries' affairs.<br />B. U.S. doctrine prevented other nations from intervening in the Americas.<br />C. Latin America had asked the U.S. to be an international police power.<br /><br />## Step 3<br />The correct answer is B. U.S. doctrine prevented other nations from intervening in the Americas. This is because the Roosevelt Corollary to the Monroe Doctrine, which was a policy statement by President Roosevelt, stated that the United States would intervene in conflicts between European and Latin American countries to enforce legitimate claims of the European powers, rather than having the Europeans press their claims directly.