In order to execute imperialism, it is very important to have the support of the people. The most efficient way to have and maintain the support of the people is to promote nationalism.
Explanation:
Nationalism is very different than patriotism. Patriotism can be define as the love of being from a country with respecting also the sovereignty of other nations. On the other hand, nationalism is an aggressive love for a country without considering the sovereignty of other nations. Nationalism is the key element to go to war. The leader of a nation can never go to war without practicing nationalism on his people as his political tool.
The main reason the U.S did this is because of cheap labor cost the United states us able to control and own industries in these areas through transnational cooperations