The United States not only feared European intervention in Florida, but also in the Pacific Northwest and in Latin America. In 1821, Russia claimed control of the entire Pacific coast from Alaska to Oregon and closed the area to foreign shipping. This development coincided with rumors that Spain, with the help of its European allies, was planning to reconquer its former Latin American colonies.
European intervention threatened British as well as American interests. Not only did Britain have a flourishing trade with Latin America, which would decline if Spain regained its New World colonies, it also had claims to territory in the Oregon country of the Pacific Northwest. In 1823, British Foreign Minister George Canning (1770-1827) proposed that the United States and Britain jointly announce their opposition to further European intervention in the Americas.
Secretary of State John Quincy Adams opposed a joint declaration. He convinced President Monroe to make a unilateral declaration of American policy, which has since become known as the Monroe Doctrine. He announced that the Western Hemisphere was henceforth closed to further European colonization. Monroe also said that the United States would not interfere in internal European affairs.
For much of the nineteenth century, the United States lacked the military strength to prevent European intervention in the New World. But since European meddling threatened British as well as American interests, the Monroe Doctrine was enforced by the Royal Navy. Nevertheless, for the American people, the Monroe Doctrine was the proud symbol of American hegemony in the Western Hemisphere. Unilaterally, the United States had defined its rights and interests in the New World.
The occasion has been judged proper for asserting, as a principle in which the rights and interests of the United States are involved, that the American continents, by the free and independent condition which they have assumed and maintain, are henceforth not to be considered as subjects for future colonization by any European powers....
The citizens of the United States cherish sentiments the most friendly in favor of the liberty and happiness of their fellow-men on that side [the European side] of the Atlantic. In the wars of the European powers in matters relating to themselves we have never taken any part, nor does it comport with our policy so to do. It is only when our rights are invaded or seriously menaced that we resent injuries or make preparation for our defense. With the movements in this hemisphere we are of necessity more immediately connected, and by causes which must be obvious to all enlightened and impartial observers. The political system of the allied powers is essentially different in this respect from that of America.... We owe it, therefore, to candor and to the amicable relations existing between the United States and those powers to declare that we should consider any attempt on their part to extend their system to any portion of this hemisphere as dangerous to our peace and safety. 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 an unfriendly disposition toward the United States. In the war declared between those new Governments and Spain we declared our neutrality at the time of their recognition, and to this we have adhered, and shall continue to adhere, provided no change shall occur which, in the judgment of the competent authorities of this Government, shall make a corresponding change on the part of the United States indispensable to their security....
Our policy in regard to Europe, which we adopted at an early stage of the wars which have so long agitated that quarter of the globe, nevertheless remains the same, which is not to interfere in the internal concerns of any of its powers; to consider the government de facto as the legitimate government for us; to cultivate friendly relations with it, and to preserve those relations by a frank, firm, and manly policy, meeting in all instances the just claims of every power, submitting to injuries from none.