What was the central message of the Monroe Doctrine?

The central message of the Monroe Doctrine was to warn against European expansion in the Americas. Established in 1823, the doctrine articulated a clear stance that the Western Hemisphere was no longer open to colonization or interference by European powers. This policy was rooted in the context of post-colonial America, where the newly independent nations were concerned about the potential resurgence of European colonial ambitions. The United States asserted that any attempt by a European nation to interfere in the affairs of countries in the Americas would be seen as a threat to U.S. peace and safety. This was significant because it marked an early assertion of American influence and a commitment to protect neighbors in the hemisphere against European dominance.

While the other options mention elements that do not align with the Monroe Doctrine's principles, the doctrine fundamentally emphasized a defensive posture regarding any foreign meddling in the Western Hemisphere, establishing a key part of U.S. foreign policy for years to come.