The Monroe Doctrine, expressed in 1823, proclaimed the United States' opinion that European powers should no longer colonize the Americas or interfere with the affairs of sovereign nations located in the Americas, such as the United States, Mexico, Gran Colombia and others. In return, the United States planned to stay neutral in wars between European powers and in wars between a European power and its colonies. However, if these latter type of wars were to occur in the Americas, the U.S. would view such action as hostile toward itself.