The stand alone thread of the Assistant AG's letter is here:
http://freerepublic.com/focus/f-news/1545787/posts
Under Article II of the Constitution, including in his capacity as Commander in Chief, the President has the responsibility to protect the Nation from further attacks, and the Constitution gives him all necessary authority to fulfill that duty. See, e.g., Prize Cases, 67 U.S. (2 Black) 635, 668 (1863) (stressing that if the Nation is invaded, "the President is not only authorized but hound to resist by force . . . . without waiting for any special legislative authority"); Campbell v. Clinton, 203 F.3d 19,27 (D.C. Cir. 2000) (Silberman, J., concurring) ("[T]he Prize Cases . . . stand for the proposition that the President has independent authority to repel aggressive acts by third parties even without specific congressional authorization, and courts may not review the level of force selected."); id. at 40 (Tatel, J., concurring). The Congress recognized this constitutional authority in the preamble to the Authorization for the Use of Military Force ("AUMF") of September 18, 2001, 115 Stat. 224 (2001) ("[T]he President has authority under the Constitution to take action to deter and prevent acts of international terrorism against the United States."), and in the War Powers Resolution, see 50 U.S.C. § 1541(c) ("The constitutional powers of the President as Commander in Chief to introduce United States Armed Forces into hostilities[] . . . [extend to] a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.").