Why wasn't there an American Empire?

Given the United States' unmatched wealth, technological advancements, military power, and general diplomatic influence, why did we never establish an actual empire like European states did in the past or the way China may be trying to do now?<br><br>I understand that there are a lot of arguments against the idea of an American Empire (ethics, logistics, general sentiments of Americans), but history has seemed to demonstrate time and time again that those kinds of concerns matter little to world powers. Also, although the U.S. is not an empire in the classical sense, it does have a significant network of military bases and general partnerships with nations around the world.