dorky
The Doctrine was issued at a time when nearly all Latin American colonies of Spain and Portugal had achieved or were gaining independence from the Portuguese and Spanish Empires. Peru and Bolivia would become independent in 1825, leaving only Cuba and Puerto Rico under Spanish rule. The United States, working in agreement with Britain, wanted to guarantee that no European power would move in.
President James Monroe stated the doctrine during his seventh annual State of the Union Address to Congress. The term "Monroe Doctrine" itself was first used in 1850 and by the end of the nineteenth century, Monroe's declaration was seen as a defining moment in the foreign policy of the United States and one of its longest-standing tenets. It would be invoked by many U.S. statesmen and several U.S. presidents, including Theodore Roosevelt, John F. Kennedy, Lyndon B. Johnson, Ronald Reagan and many others.
At the time, the U.S. government feared the victorious European powers that emerged from the Congress of Vienna, following the defeat of Napoleon, would once again gravitate towards the establishment of empires. Great Britain shared the general objective of the Monroe Doctrine, and wanted to keep other European powers from further colonizing the New World. The British were afraid that Britain's trade with the New World would be harmed if the other European powers further colonized it. For much of the early years of the Monroe Doctrine, Great Britain was the only nation capable of enforcing it through the use of its navy. The United States still lacked sufficient naval capabilities to contribute to the effective enforcement of the doctrine. Allowing Spain to re-establish control of its former colonies would have cut Great Britain off from its profitable trade with the region. For that reason, Great Britain's Foreign Minister George Canning proposed to the United States that they mutually declare and enforce a policy of separating the new world from the old. The United States resisted a joint statement because of the recent memory of The War of 1812, leading to the Monroe administration's unilateral statement.
In 1829, rumors spread that a group of British merchants tried to strike a deal with Mexico offering $5,000,000 for Texas which would be held under the protection of Great Britain. Ultimately, nothing came of the British merchants' offer but the rumor was proven to be true, in clear violation of the Monroe Doctrine.
The essence of the Monroe Doctrine is expressed in two key passages. The first is the introductory statement:
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 second key passage, a fuller statement of the Doctrine, is addressed to the "allied powers" of Europe:
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.