However, to do so would be to engage in a horrible revisionist version of history. The development of modern America was based on the concept of manifest destiny and would not have occurred without the systemic deprivation of the rights of indigenous people. Attacking Native Americans, killing off tribes, killing off of buffalo for sport and thus depriving tribes of their food sources, and forcing Native Americans into reservations are all examples of imperialistic behavior. In addition, the development of the plantation system, the history of slavery, and the post-emancipation degradation of African-Americans are likewise examples of American imperialism. Unfortunately, imperialism is a traditional American value, though those values are changing. Imperialism for America changed dramatically in the late 19th century, with the Emancipation Proclamation and the passage of the 13th, 14th, and 15th Amendments, which sought to guarantee equal rights to people regardless of race. While these promises have yet to be completely fulfilled, they symbolized...

government's recognition that defining one race as inferior to another was improper and un-American. Of course, society did not recognize that change overnight, and it has been a long and difficult struggle towards de facto equality in the United States. However, the change away from imperialism is evident when one views America's foreign policy. America does not actively engage in the development of colonies and has given some areas, such as Guam and Puerto Rico, substantial amounts of self-rule.
One interesting thing about imperialism is that the controlling powers have shifted from governments to economic entities. For example, there is no official American government presence in China that dictates that poorly paid Chinese people manufacture goods for American consumers; however, the reality is that Western nations continue to exploit people in other countries. This practice is no longer considered imperialism, but certainly reflects the same type of cultural and racial superiority that encouraged imperialistic expansion.