“…With the existing colonies or dependencies of any European power we have not interfered and shall not interfere. But with the Governments who have declared their independence and maintained it, and whose independence we have, on great consideration and on just principles, acknowledged, we could not view any interposition for the purpose of oppressing them, or controlling in any other manner their destiny, by any European power in any other light than as the manifestation of any unfriendly disposition toward the United States…” President James Monroe proclaimed the Monroe Doctrine in 1823. What is the main point of the doctrine, as shown in this excerpt?