National Style in the United States

Having a national style means having a distinguishing exterior dialogue that sets you apart from the rest of the world. America started out with the Grecian/Greek revival style because it was a way to communicate authority over the people. The Greeks displayed the honorary means of acknowledging their superiors this way, and we borrowed that language for our benefit. 

As a society now, we are a primarily corporate, being the wealthiest country in the world. National style today shows our class and sophistication with large sun reflecting skyscrapers and other "modern" boxy elements in our exteriors. We build up more not to communicate with the Gods, like the ancient Greeks, but to show that we are in essence sharing that superiority. This stroke of our egos is well displayed by the Willis Tower in Chicago Illinois.