Long, but poignant.
"America, in the assembly of nations, since her admission among them, has invariably, though often fruitlessly, held forth to them the hand of honest friendship, of equal freedom, of generous reciprocity. She has uniformly spoken among them, though often to heedless and often to disdainful ears, the language of equal liberty, of equal justice, and of equal rights. She has, in the lapse of nearly half a century, without a single exception, respected the independence of other nations while asserting and maintaining her own. She has abstained from interference in the concerns of others, even when conflict has been for principles to which she clings, as to the last vital drop that visits the heart. [...] She well knows that by once enlisting under other banners than her own, were they even the banners of foreign independence, she would involve herself beyond the power of extrication, in all the wars of interest and intrigue, of individual avarice, envy, and ambition, which assume the colors and usurp the standard of freedom. The fundamental maxims of her policy would insensibly change from liberty to force. The frontlet on her brows would no longer beam with the ineffable splendor of freedom and independence; but in its stead would soon be substituted an imperial diadem, flashing in false and tarnished lustre the murky radiance of dominion and power. She might become the dictatress of the world; she would be no longer the ruler of her own spirit."
-John Quincy Adams, 4 July 1821 address as Secretary of State to the U.S. House of Representatives.