The Monroe Doctrine
The Monroe Doctrine was a foreign policy for the US. It regarded all Latin American countries. The doctrine stated that any attempts to colonize America or interfere, it would be seen as a sign of aggression and the US would have to interfere. The Monroe Doctrine began to promote nationalism because, America has claims to all American territory, that was not already claimed. This made American have aspirations of keeping out any foreigners of their "great nation".
This primary source is the original document/ doctrine to out the foreign policy in place.