Police in space

The United States has a strong and well-founded aversion to the use of military force within its own borders. There have been exceptions -- President Eisenhower’s deployment of the 101st Airborne to enforce desegregation in Little Rock, Ark., was perhaps the most vivid -- but for the most part the nation has prospered by the separation of its police and military, which has helped protect the public from suppression and the military from distraction.

The underlying principle is enshrined in the Posse Comitatus Act, enacted soon after the Civil War and intended to bar the Army from acting as a police force -- originally, to bar it from enforcing order in the Southern states. Although written with the Army specifically in mind, it has since been applied to the other branches of the military and has helped to deter many attempts, well-meaning and otherwise, to press the military into police work, for instance in the “war on drugs.”

But the “war on terror,” which reaches inside American borders as well as outside, inevitably has caused some to ask whether the military should fight it at home too. Specifically, the Department of Homeland Security, without so much as a phone call to Congress, has developed a program to draw on military surveillance satellites to help local police. Under the program as envisioned, police or sheriff’s departments could request targets -- a suspected drug dealer’s house, say. A National Applications Office in the Homeland Security Department would consider the requests and, on approval, attempt to deliver the information to local law enforcement, which it refers to as its “customers.”

That’s tempting. What’s the harm in printing out high-resolution satellite images -- which the government already is producing -- and sharing them with officials who might use them to thwart criminals? In most cases, they would simply be photographs capturing activity outdoors, where there is little reasonable expectation of privacy. There could, however, be exceptions -- critics warn of infrared sensors, advanced radar, acoustic scans and devices to pinpoint various structural materials.

Such applications help to highlight at least three immediate reasons to greet this idea with skepticism. First, it turns the military away from its essential mission -- fighting America’s enemies abroad -- and toward an area where it doesn’t have much expertise, namely spying on those it’s charged to defend. Second, redirecting spy cameras and sensors onto American rooftops offers up perilous possibilities in mission and technology creep. And third, this administration long ago lost the public’s trust on domestic surveillance.

Philosophically, refocusing satellites on the home front represents a new dimension in warrantless surveillance. Cameras said to be able to make out objects that can fit in one’s hand would be trained on backyards; at some angles, through windows; and with some technologies, through walls and roofs, probing for heat or other indicators of life or malfeasance. The government’s surveillance capabilities would be radically expanded. All of that should alarm anyone who values privacy in the home or who questions the virtue of a snooping government.

Practically, the ramifications cut another way. Imagine the criminal defendant brought to court because a military satellite spotted a marijuana patch in his backyard. He would be entitled to challenge the imagery that supplied evidence against him. Is the Pentagon ready to disclose the specs on its super-secret devices in order to help county sheriffs round up pot farmers?

The sanctity of one’s home is not an ideological principle; it is an American one. Indeed, it was no less a conservative than Justice Antonin Scalia who wrote for the Supreme Court in 2001 in ruling that a government thermal analysis of a home was an unlawful “search.” His reasoning deserves repeating as the administration and Congress consider the use of satellites to crimp still further the remaining privacy that Americans enjoy. In Scalia’s words: “Where, as here, the government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a ‘search’ and is presumptively unreasonable without a warrant.”