American peace is not due to the fact that we have a common executive, a Congress, and a Supreme Court, useful as all of these instruments may be. It exists because any citizen of the United States equally with any other citizen has a right in perfect freedom to pass state borders with all his family and property; to import and export from place to place within the limits of the United States any sort of property he pleases without hindrance from any state authority; to gain access to and from the seas without any local interference whatsoever.
