HISTORY and political science unite in bearing testimony to the fact that the power to conduct international relations is a power pertaining to the executive.
"With regard to foreign concerns," says Blackstone, writing shortly before the American Revolution, and widely studied by American statesmen of the ensuing decades,
the king is the delegate or representative of his people. It is impossible that the individuals of a state, in their collective capacity, can transact the affairs of that state with another community equally numerous as themselves. Unanimity must be wanting to their measures, and strength to the execution of their counsels. In the king therefore, as in a centre, all the rays of his people are united, and form by that union a consistency, splendor, and power, that make him feared and respected by foreign potentates; who would scruple to enter into any engagement that must afterwards be revised and ratified by a popular assembly. What is done by the royal authority, with regard to foreign powers, is the act of the whole nation; what is done without the king's concurrence, is the act only of private men.1
It is . . . the king's prerogative to make treaties, leagues, and alliances with foreign states and princes.
"During the colonial period," asserts the Supreme Court of the United States, international "powers were possessed exclusively by and were entirely under the control of the Crown."2
From such unequivocal pronouncements by authorities superlatively compelling to the American legal mind there would seem to be no appeal -- and no need for further evidence. Thomas Jefferson, moreover, is quoted as considering that "the transaction of____________________