Why does White describe the American idea as having “explosive power”?

Unlike other nations, America and its citizens are a nation born of an idea; it was not a place that crested the United States government but an idea. This is the explosive power of the American idea, the world had never seen a country like this, and never before had a country been made up of citizens from all over the world. People came here in droves, and if it were possible they still would.

sorry, second line typo....... crested should be created!