<p>This memo considers the use of military force to prevent or deter terrorist activity domestically and concludes that, “the President has both constitutional and statutory authority to use the armed forces in military operations, against terrorists, within the United States. We believe that these operations generally would not be subject to the constraints of the Fourth Amendment . . . .” The memo is criticized and partly repudiated in Steven Bradbury’s 10/6/08 memo.</p>
U.S. Department of Justice Seal U.S. Department of Justice Office of Legal Counsel Washington. DC 20530 October 23,2001 Office of the Deputy Assistant Attorney General MEMORANDUM FOR ALBERTO R. GONZALES COUNSEL TO THE PRESIDENT -WILLIAM J. HAYNES, II GENERAL COUNSEL DEPARTMENT OF DEFENSE FROM: John C. Yoo - Signature of John C. Yoo Deputy Assistant Attorney General Robert J. Delahunty - Signature of Robert J. Delahunty Special Counsel RE: Authority for Use of Military Force To Combat Terrorist Activities Within the United States You have asked for our Office's views on the authority for the use of military force to prevent or deter terrorist activity inside the United States. Specifically, you have asked whether the Posse Comitatus Act, 18 U.S.C. § 1385 (1994), limits the ability of the President to engage the military domestically, and what constitutional standards apply to its use. We conclude that the President has ample constitutional and statutory authority to deploy the military against international or foreign terrorists operating within the United States. We further believe that the use of such military force generally is consistent with constitutional standards, and that it need not follow the exact procedures that govern law enforcement operations. Our analysis falls into five parts. First, we review the President's constitutional powers to respond to terrorist threats in the wake of the September 11, 2001 attacks on the World Trade Center and the Pentagon. We consider the constitutional text, structure and history, and interpretation by the executive branch, the courts and Congress. These authorities demonstrate that the President has ample authority to deploy military force against terrorist threats within the United States-Second, we assess the legal consequences of S.J. Res. 23, Pub. L. No. 107-40, 115 Stat. 224 (2001), which authorized the President to use force to respond to the incidents of September 11. Enactment of this legislation recognizes that the President may deploy military force domestically and to prevent and deter similar terrorist attacks. Third, we examine the Posse Comitatus Act, 18 U.S.C. § 1385, and show that it only applies to the domestic use of the Armed Forces for law enforcement purposes, rather than for the performance of military functions. The Posse Comitatus Act itself contains an exception that allows the use of the military when constitutionally or statutorily authorized, which has occurred in the present circumstances. Fourth, we turn to the question whether the Fourth Amendment would apply to the use of the military domestically against foreign terrorists. Although the situation is novel (at least in the nation's recent experience), we think that the better view is that the Fourth Amendment would not apply in these circumstances. Thus, for example, we do not think that a military commander carrying out a raid on a terrorist cell would be required to demonstrate probable cause or to obtain a warrant. Fifth, we examine the consequences of assuming that the Fourth Amendment applies to domestic military operations against terrorists. Even if such were the case, we believe that the courts would not generally require a warrant, at least when the action was authorized by the President or other high executive branch official. The Government's compelling interest in protecting the nation from attack and in prosecuting the war effort would outweigh the relevant privacy interests, making the search or seizure reasonable. I. The situation in which these issues arise is unprecedented in recent American history. Four coordinated terrorist attacks took place in rapid succession on the morning of September 11, 2001, aimed at critical Government buildings in the nation's capital and landmark buildings in its financial center. The attacks caused more than five thousand deaths, and thousands more were injured. Air traffic and telecommunications within the United States have been disrupted; national stock exchanges were shut for several days; damage from the attack has been estimated to run into the tens of billions of dollars. Hundreds of suspects and possible witnesses have been taken into custody, and more are being sought for questioning. In his Address to a Joint Session of Congress and to the American People on September 20, 2001, President Bush said that "[o]n September the 11th, enemies of freedom committed an act of war against our country." President's Address to a Joint Session of Congress (Sept. 20, 2001), available at