Pete duPont on spying:
Benjamin Franklin (whose 300th birthday is today) would not have thought so. In 1776 he and his four colleagues on the Continental Congress's foreign affairs committee (called the Committee of Secret Correspondence) unanimously agreed that they could not tell the Congress about the covert assistance France was giving the American Revolution, because it would be harmful to America if the information leaked, and "we find by fatal experience that Congress consists of too many members to keep secrets."
While the Constitution was being ratified in 1787 John Jay (later the first chief justice) in Federalist No. 64 praised the Constitution for giving the president power "to manage the business of intelligence in such manner as prudence may suggest." And of course Article II of the ratified Constitution gave the president the nation's "Executive power" and states that "the President shall be the Commander in Chief of the Army and Navy of the United States."
When in the early 1800s President Jefferson hired foreign mercenaries to invade Tripoli and free American hostages, he did not inform Congress in advance. In 1818, when a controversy arose over a diplomatic mission abroad, House Speaker Henry Clay told his colleagues that since the president had paid for the mission with his contingent fund it would not be "a proper subject for inquiry."
So it is clear that the Constitution's original intent was that the president had the authority to take undisclosed foreign actions to protect America.
He goes on to cover legislative and judicial history upholdiong the President's right as Commander in Chief to take action to defend America without warrants or Congressional knowledge.