Has the United States been Imperialistic?

In our history, the United States has been a part of many events that could make people believe we have been imperialistic, and when we really take a close look at these events, we see that the US has been imperialistic, just not on the large scale that the Europeans have been. Some reasons that show that we have been imperialistic come from our interactions with Iraq and Afghanistan, the Mexican- American War, and the our interactions with Japan in the early twentieth century. In Iraq and Afghanistan, we didn't set up colonies as the Europeans did, yet we came in and tried to establish new governments that reflected our own constitution, founded in liberty and equality, just as the Europeans came in and tried to establish their ideas of civilization in the age of imperialism. In the Mexican-American War, we had expanded westward into Mexican territory and then fought a war over the land disputes, and came out on top with a huge expansion of territory that gave us some of the largest states in our nation. Finally, with Japan, we headed across the Pacific Ocean around the same time that Europeans were expanding into China and used gunboat diplomacy to force Japan to open its trading ports to the rest of the world. Some ways that show we haven't been imperialistic are the Panama Canal, Guam and Puerto Rico, and in some ways the Civil War. The Panama canal shows that we haven't been imperialistic as we could have easily taken over the small country for our own possession, yet we left them alone, helped build and fund the important canal, and left Panama alone after that. We did not force our government upon them or abuse the native people's ways of life, and we now have no control over the country. In Guam and Puerto Rico, they are now both United States Territories that we have gained, yet they are self sustaining and are free to have commerce and run their territory apart from our government. Finally, some argue that the Civil War shows how the United States has been imperialistic as the Union retook the Confederacy and reunited the country, but that is a false claim as it was an internal conflict and no territory was changed because of it, the country was just reunited.