The special diplomatic agent has played in the history of American foreign policy an important and, it is safe to say, unique role. The names of Colonel House and Harry Hopkins come, of course, right away to mind. But there have been others: John Quincy Adams, Ber­ nard M. Baruch, Henry Clay, Albert Gallatin, James Monroe, John Randolph, Daniel Webster, Wendell Wilkie, for instance. At the beginning of American history, the use of the special agent was primarily due to the scarcity of available talent. Later it was due to the low quality of many diplomatic representatives, chosen for political reasons and without regard for their diplomatic qualifications. More recently, the President has availed himself of the special agent in order to make sure that his will prevails in the conduct of American foreign policy. The institution of the special agent is indeed inseparable from the preeminent, contested and uncertain role the President plays in the determination of American foreign policy. Since the Constitution is silent on that point, the ultimate determi­ nation of American foreign policy has been throughout American history a subject ot controversy between the President and Congress.