The Pentagon has deployed sophisticated military spy planes in the Washington metropolitan area as part of the manhunt for the sniper who has fatally shot nine people in a killing spree in suburban Virginia and Maryland.

The decision to use the military in an ongoing criminal investigation is virtually unprecedented and constitutes a clear breach of the Posse Comitatus Act, a 125-year-old law barring the armed forces from participating in law enforcement.

Pentagon and Justice Department lawyers huddled on the issue and came up with a set of protocols aimed at circumventing the law. While the US Army will operate the planes, each will carry an FBI agent aboard who will serve as an intermediary between soldiers in the plane and police forces on the ground.

The RC-7 aircraft are equipped with electro-optical and infrared sensors and are able to conduct surveillance over large areas during both day and night. The planes are also able to instantly transmit high-resolution imagery to the ground.

The latest victim in the sniper killings was a 47-year-old woman who worked as an intelligence analyst for the FBI, one of the agencies that requested military intervention in the case. Secretary of Defense Donald Rumsfeld signed an order deploying the aircraft on Tuesday night.

Involvement in the manhunt for the sniper may not be the military’s only connection to the case. According to law-enforcement officials, the FBI has also asked the Pentagon for a list of recently discharged soldiers who went through one of the military’s sniper training schools.

The military deployment in the search is only part of a massive mobilization of federal resources. Hundreds of FBI, Bureau of Alcohol, Tobacco and Firearms, and even Secret Service agents have been assigned to the case.

The timing as well as the scope of this response suggests that the Bush administration is once again exploiting a tragedy and public fears to press an anti-democratic political agenda: to accustom the population to the militarization of American society, strengthen federal police powers, and implement sweeping governmental changes.

The first of the shootings took place October 2, just one day after the newly created Northern Command began its operations. The command for the first time places a general in charge of military personnel whose theater of operations is the US itself.

Air Force General Ralph E. Eberhart, the chief of the Northern Command, called last July for the military to be granted greater power to operate within the US as part of the Bush administration’s “war on terrorism.”

“My view has been that Posse Comitatus will constantly be under review as we mature this command,” the General told the New York Times in an interview. “... There are some situations where there’s no other alternatives, and federal forces have to be used to secure the safety and security of our people.”

The general’s comments echoed the views expressed by the right-wing civilian leadership of the Pentagon, which is pressing for an expanded role for the military in domestic policing. Deputy Defense Secretary Paul Wolfowitz, for example, told a congressional panel last year that he “strongly agreed” with those advocating a sweeping reexamination of the Posse Comitatus doctrine.

The act, passed in 1878 to end military occupation of the Reconstruction-era South, prohibits the armed forces from enforcing civil laws “except in cases and under circumstances authorized by the Constitution or Act of Congress.”

In recent years, successive administrations have whittled away at the restriction, particularly in relation to the “war on drugs,” allowing the use of military equipment, training and facilities to aid police agencies. Anything more than that, however, is supposed to require the president’s declaration of a national emergency.

Bush administration measures have already made significant inroads into the Posse Comitatus restrictions. The deployment of armed National Guardsmen at airports nationwide was undertaken under a federal initiative, but the White House requested that state governors order the deployment to provide a legal fig leaf for the de facto violation of the Posse Comitatus law.

While providing little in the way of added safety for air passengers, the deployment had the effect of accustoming the population to the daily stationing of armed troops in public places.

Meanwhile, there have been persistent reports of the use of military intelligence for domestic spying, both against Arab and Muslim communities in the US, as well as at demonstrations, such as the protest that accompanied last month’s meetings of the International Monetary Fund and World Bank in Washington.

The sniper killings have taken place against the political backdrop of the White House’s attempt to ram through Congress legislation creating its new Homeland Security Department, a key element in the administration’s police-state buildup. Bush appeared with his entire cabinet at the White House Monday to denounce the Senate’s Democratic leadership for failing to accept the president’s right to deny any and all of the new department’s employees the right to union representation.