Individuals tend to be more moral than societies and governments, as philosopher Reinhold Niebuhr has argued. That is to say, one can't expect that the government of the United States, or the leadership of any empire or nation for that matter, would act in a way that is consistent with what most people would call moral.
Nations act in their own self-interests. While sometimes using realpolitik, acting in the national interest above morality, is also a moral action, this is usually more coincidence than anything else. To act in a way that put morality above economic and security is called altruism, and nations that have come close to practicing it have often not survived long.
It is an interesting question/topic, and I do believe it would be easier for the US to act in a more or less moral manner with regards to the peoples of the world if we were no longer an empire, or no longer dependent on energy from foreign sources.