<span>The biggest change was the passing of the Civil Rights act, which led to trouble of segregation and such among the states. Also the idea of making education available to everybody also bloomed during this time.</span>
I think it's the western and eastern fronts.
The answer is the Monroe Doctrine. This Doctrine was stated by the fifth President of the United States, James Monroe, on December 2, 1823, and became the foreign policy of the nation for many years.
The doctrine stated that:
●<em> The efforts of European nations to colonize land in North or South America, are considered as acts of aggression, requiring U.S. intervention</em>.
●<em> Any interference by European nations with states of North or South America would also be perceived as acts of aggression and would call for U.S. intervention</em>.
● <em>The United States would not interfere with existing European colonies</em>.
● <em>The United States would not get involved with the internal affairs of European nations</em>.
