Perhaps you have in mind the Monroe Doctrine (and Theodore Roosevelt's Corollary and Manifest Destiny). If so, you will find information about those justifications for U.S. influence at http://www.state.gov/r/pa/ho/time/jd/16321.htm
the monroe doctrine
the monroe doctrine
the monroe doctrine
Western hemisphere.
The Roosevelt Corollary
yes
Monroe Doctrine
James Monroe(: he made the monroe doctrine
The US is in the northern hemisphere and in the western hemisphere.
Would take care of the Western Hemisphere without assistance or interference from the Olde World.
It is in a north western hemisphere
After the revolution the US stated that any attempt to colonize the western hemisphere would not be tolerated, and would be dealt with militarily.