How would the United States have enforced the Monroe Doctrine if its declaration had been immediately challenged by any of the European powers at which it was aimed

The Monroe Doctrine December 2, 1823 How would the United States have enforced the Monroe Doctrine if its declaration had been immediately challenged by any of the European powers at which it was aimed? Which of the powers of Europe would have been most likely to have asserted its claim to possession of colonies in the Western Hemisphere and how would they have been able to prosecute such an assertion? Give details and be specific in your theorizing.