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This fact is amply borne out by history. This Nation has a long tradition of wartime enemy surveillance?a tradition that can be traced to George Washington, who made frequent and effective use of secret intelligence. One source of Washington?s intelligence was intercepted British mail. See Central Intelligence Agency, Intelligence in the War of Independence 31, 32 (1997). In fact, Washington himself proposed that one of his Generals ?contrive a means of opening [British letters] without breaking the seals, take copies of the contents, and then let them go on.? Id. at 32 (?From that point on, Washington was privy to British intelligence pouches between New York and Canada.?). And for as long as electronic communications have existed, the United States has intercepted those communications during wartime, and done so, not surprisingly, without judicial warrants. In the Civil War, for example, telegraph wiretapping was common and provided important intelligence for both sides. In World War I, President Wilson authorized the military to intercept all telegraph, telephone, and cable communications into and out of the United States; he inferred the authority to do so from the Constitution and from a general congressional authorization to use military force that did not mention anything about such surveillance. See Exec. Order No. 2604 (Apr. 28, 1917). So too in World War II; the day after the attack on Pearl Harbor, President Roosevelt authorized the interception of all communications traffic into and out of the United States. The terrorist surveillance program, of course, is far more focused, since it involves the interception only of international communications that are linked to al Qaeda.
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Section. 2.

The President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States; he may require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any Subject relating to the Duties of their respective Offices, and he shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.
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