... the roots of U.S. imperialism go all the way back to Jamestown and Plymouth Rock -- let's not forget that the United States is the product of a project to systematically seize control of Central North America from its native inhabitants for peoples of European descent.
Except that wasn't the "project." Europeans didn't come to North and South America with the primary goal of taking the continents away from someone else. They wanted the land and resources on the continents yes, but the fact that there was a indigenous population was irrelevant. Were there to have been no natives present, the Europeans still would have come.
European #1: "There's no one here to subjugate."
European #2: "Damn, well let's go home then".