T he Posse Comitatus Act, enacted in 1878 and now codified at 18 U.S.C. § 1385, is perhaps the most tangible expression of an American tradition, born in England and developed in the early years of our nation, that rebels against military involvement in civilian affairs. The Declaration of Independence listed among our grievances against Great Britain that the King had "kept among us, in times of peace, Standing Armies without the consent of our legislatures," had "affected to render the Military independent of and superior to the civil power." The Articles of Confederation addressed the threat of military intrusion into civilian affairs by demanding that the armed forces assembled during peacetime be no more numerous than absolutely necessary for the common defense, and by entrusting control to civil authorities within the states. The Constitution continued the theme. It provided that a civilian, the President, should be the Commander in Chief of the Army and Navy of the United States and that civilian authorities, the Congress, should be solely empowered to raise and support Armies, provide and maintain a Navy, and make rules for their government and regulation. The Bill of Rights limited the quartering of troops in private homes, U.S. Const. Amend. III, and noted that "a well-regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed," U.S. Const. Amend. II. The Constitution, on the other hand, explicitly permitted the Congress to provide for calling out the militia to execute the laws, suppress insurrection, and repel invasion, U.S. Const. Art. I, § 8, cl.16. Soon after Congress was first assembled under the Constitution, it authorized the President to call out the militia, initially to protect the frontier against "hostile incursions of the Indians," and subsequently in cases of invasion, insurrection, or obstruction of the laws, in aid of a state government or where federal law met resistance. These authorities were used to put down the "Whiskey Rebellion" and other armed resistance to the revenue laws, labor strikes and race riots, and bands of desperados in the territories. Congress in some cases specifically authorized the use of the armed forces to execute civilian laws in cases that did not amount to insurrection, including enforcement of embargoes and the neutrality laws. The President's authority to call upon the state militia to aid in putting down insurrections is reminiscent of the authority enjoyed by the sheriff at common law to call upon the posse comitatus. In the beginning, the two were comparable but unrelated. Even though Congress empowered the President to call out the militia to overcome obstructions to law enforcement, it continued to vest the federal equivalent of the sheriff, the federal marshal, with the power to call forth the posse comitatus in performance of his duties. In addition, Congress sometimes authorized recourse to the posse comitatus for the enforcement of particular statutes. Under the Fugitive Slave Act, for instance, owners whose slaves had escaped to another state were entitled to an arrest warrant for the slaves and to have the warrant executed by federal marshals. The marshals in turn might "summon and call to their aid the bystanders, or posse comitatus of the proper county ... [and] all good citizens [were] commanded to aid and assist in the prompt and efficient execution of this law, whenever their services may be required, as aforesaid, for that purpose," 9 Stat. 462, 463 (1850). Attorney General Caleb Cushing declared that the "bystanders" contemplated by the Fugitive Slave Act might include members of a state militia even when not in federal service, and they did encompass members of the armed forces by virtue of their duties as citizens as part of the posse comitatus. Following the Civil War, the use of federal troops to execute the laws, particularly in the states that had been part of the Confederacy, continued even after all other political restrictions had been lifted. In response, Congress passed the Posse Comitatus Act as part of an Army appropriations bill in 1878. With the exception of a reference to the Air Force, it has remained essentially unchanged ever since, although Congress has authorized a substantial number of exceptions and has buttressed the act with an additional proscription against use of the armed forces to make arrests or conduct searches and seizures. While the terrorist attacks of September 11, 2001 led some to call for a reexamination of the role of the military in domestic law enforcement, Congress, in establishing the Department of Homeland Security, expressed its sense reaffirming the continued importance and applicability of the Posse Comitatus Act. 6 U.S.C. § 466. The Posse Comitatus Act does not apply "in cases and under circumstances expressly authorized by the Constitution," 18 U.S.C. § 1385. It has been observed that the Constitution contains no provision expressly authorizing the use of the military to execute the law, that the exception was included as part of a face-saving compromise, and that consequently it should be ignored. The older commentaries suggest that the word "expressly" must be ignored, for otherwise in their view the Posse Comitatus Act is a constitutionally impermissible effort to limit the powers of the President. The regulations covering the use of the armed forces during civil disturbances do not go quite that far, but they do assert two constitutionally based exceptions—sudden emergencies and protection of federal property. The question of whether the constitutional exception includes instances where the President is acting under implied or inherent constitutional powers is one the courts have yet to answer. The Posse Comitatus Act does not apply where Congress has expressly authorized use of the military to execute the law. Congress has done so in three ways: (1) by giving a branch of the armed forces civilian law enforcement authority; (2) by establishing general rules for certain types of assistance; and (3) by addressing individual cases and circumstances with more narrowly crafted legislation. Thus it has vested the Coast Guard, a branch of the armed forces, with broad law enforcement responsibilities. Second, over the years it has passed a fairly extensive array of particularized statutes, like those permitting the President to call out the armed forces in times of insurrection and domestic violence, 10 U.S.C. §§ 251-255. Finally, it has enacted general legislation authorizing the armed forces to share information and equipment with civilian law enforcement agencies, 10 U.S.C. §§ 271-284. These last general statutes were crafted to resolve questions raised by the so-called Wounded Knee cases (see below). The legislation contains both explicit grants of authority and restrictions on the use of that authority for military assistance to the police—federal, state and local—particularly in the form of information and equipment, 10 U.S.C. §§ 271-284. Section 271 specifically authorizes the armed forces to share information acquired during military operations and in fact encourages the armed forces to plan their activities with an eye to the production of incidental civilian benefits. The section allows the use of military undercover agents and the collection of intelligence concerning civilian activities only where there is a nexus to an underlying military purpose. Under §§ 272 through 274, military equipment and facilities may be made available to civilian authorities; members of the armed forces may train civilian police on the operation and maintenance of equipment and may provide them with expert advice; and military personnel may be employed to maintain and operate the equipment supplied. The authority granted in §§ 271-284 is subject to three general caveats. It may not be used in any way that could undermine the military capability of the United States; the civilian beneficiaries of military aid must pay for the assistance; and, under § 275, the Secretary of Defense must issue regulations to ensure that the authority of §§ 271 to 284 does not result in use of the armed forces to make arrests or conduct searches and seizures solely for the benefit of civilian law enforcement. The armed forces, when in performance of their military responsibilities, are beyond the reach of the Posse Comitatus Act and its statutory and regulatory supplements. Neither the act nor its legislative history resolves the question of whether the act prohibits the Army from performing its military duties in a manner which affords incidental benefits to civilian law enforcement officers. The courts and commentators believe that it does not. As long as the primary purpose of an activity is to address a military purpose, the activity need not be abandoned simply because it also assists civilian law enforcement efforts. The act is limited to "willful" misuse of the Army or Air Force. The Senate version of the original Act would have limited proscription to "willful and knowing" violations, 7 Cong. Rec. 4302 (1878); the House version had no limitation, 7 Cong. Rec. 4181 (1878). The compromise that emerged from conference opted to forbid only willful violations, but nothing in the legislative history explains what the limitation means. It seems unlikely that a court would convict for anything less than a deliberate disregard of the law's requirements. When has the Army or Air Force been used "to execute the laws"? Existing case law and commentary indicate that "execution of the law" in violation of the Posse Comitatus Act occurs when (1) the armed forces perform tasks ordinarily assigned not to them, but to an organ of civilian government; or (2) the armed forces perform tasks assigned to them solely for purposes of civilian government. While inquiries may surface in other contexts, such as the use of the armed forces to fight forest fires or to provide assistance in the case of other natural disasters, Posse Comitatus Act questions arise most often when the armed forces assist civilian police.