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

If the Monroe Doctrine had been immediately challenged by a European power, the U.S. would likely have relied on its growing naval capabilities to assert its influence in the Western Hemisphere. The U.S. could have formed alliances with emerging Latin American nations to bolster its position and deter European intervention. Additionally, the U.S. might have leveraged diplomatic pressure and economic sanctions to discourage European powers from engaging in territorial expansion in the Americas. Overall, a combination of military readiness and diplomatic maneuvering would have been key to enforcing the doctrine.