TIMELINE
1823
Declaring the Western Hemisphere off-limits to the European colonization, the Monroe Doctrine was made by President James Monroe (December 2nd).
1848
James K. Polk discourage Spain and Britain from establishing footholds in Oregon, California.
President Theodore Roosevelt added to the Roosevelt Corollary, and stated that during the event of flagrant wrong doing by a Latin American state. USA had the right to intervene in its internal affairs.
1898
Cubans were were threatening Americans and their land. The Maine was sent to help evacuate and protect Americans. America couldn't annex Cuba.
1904
America became the international police, especially in Latin America.
1906-1933
The U.S intervened in Cuba, Haiti, and Latin America.