[America's] glory is not dominion, but liberty. Her march is the march of the mind. She has a spear and a shield: but the motto upon her shield is Freedom, Independence, Peace. This has been her declaration: this has been, as far as her necessary intercourse with the rest of mankind would permit, her practice.

John Quincy Adams and American continental empire: letters, papers and speeches (ed. Chicago, Quadrangle Books, 1965)