The Roosevelt Corollary expanded the Monroe Doctrine by stating that the United States could intervene in Latin American countries to prevent European countries from doing so. It allowed the US to act as a police power in the region. While the Monroe Doctrine said European countries should not interfere in the Americas, the Roosevelt Corollary gave the US sole right to interfere if needed to keep European nations out. It was presented in response to a 1902 blockade of Venezuela by European countries due to unpaid debts.