Answer:
Imperialism is the act of colonization and domination over other nations. During the specific time period, when developed countries started to get their acts together, smaller developing countries were abused and manipulated. A prime example of this is Britain's massive empire, on which the sun evidently never set.
The US got involved with imperialism after they had taken control of the modern-day contiguous states. They soon got it in their heads that the very respectable Queen Liliuokalani was a savage and a heathen, quickly deposed her, and took Hawaii; Alaska soon followed, much more peacefully but no less vehemently contested. Further grabs at Cuba and the Philippines followed, both similarly misguided.
I'm assuming this is talking about world war I, but I'm not entirely sure. In any case, after WWI, Wilson and the idealists had finally realized the need to end isolationism. Eventually, the US did confess to their poor treatment of native Hawaiians and others who were oppressed.
