In the old days, the only way to keep tabs on a suspect was to park outside his house "on stakeout," and then try to follow him without his knowing you were on his tail. This kind of surveillance was labor-intensive, time-consuming, costly, and risky. With the advent of satellite telemetry, it became possible to track the movements of suspects accurately, continuously and inexpensively, without risk of being detected or alerting the suspect that he's being watched. You simply slapped a tracker onto the undercarriage of his car while he was parked somewhere, and watched a screen back at the station. Technology—good for the good guys, bad for the bad guys, right?

But the Supreme Court has shown a distrust of law enforcement's embrace of technology to enhance crime-fighting efficiency. For example, in Katz v. U.S. in 1967, the court ruled that police violated the Fourth Amendment by using a wiretap on a public phone booth to intercept a bookie's calls. Said the court, "The Government's activities in electronically listening to and recording the defendant's words violated [his privacy]." It would have been permissible for an officer to stand nearby and overhear Katz's conversations, but the more efficient wiretap was not allowed.

In U.S. v. Karo in 1984, a beeper case, the court worried about the prospect of "indiscriminate monitoring by electronic device." Indiscriminate monitoring by simply following a suspect around on public streets in a police car would be permissible, but electrons somehow engage the Fourth Amendment.

In Kyllo v. U.S. in 2001, the court rejected an officer's use of a thermovision imager to measure the radiant heat in the air outside a grow house. Why? Because officers had enhanced their human senses with technology: "Obtaining by sense-enhancing technology any information regarding the interior of the home that could not otherwise have been obtained without physical intrusion constitutes a search." And police use of technological devices "not in general public use," Justice Scalia wrote for the court, makes the search unreasonable. (Apparently, Justice Scalia had not seen the frequent Cadillac commercials showing that a thermo-imager in the car's grille could show Bambi darting in front of a nighttime driver.)

And in Ontario v. Quon in 2010, the court's decision said that "The court must proceed with care when considering communications made on electronic equipment" because of "rapid changes in the dynamics of communication and information transmission." Clearly, police use of technology to catch criminals makes the Supreme Court nervous. This brings us to 2012 and the recent decision on GPS tracking.

Jones v. U.S.

Antoine Jones, described in the Supreme Court's opinion merely as the "owner and operator of a nightclub in the District of Columbia," was actually charged with and convicted of possessing and conspiring to distribute 97 kilos of cocaine and one kilo of cocaine base; cash totaling $850,000 was found in his stash house (all of which would seem to make him a major narcotics trafficker-not simply a local businessman). But never mind Jones's crimes-let's just focus on whether the police unfairly used technology to catch him.

Task force officers applied for and obtained a search warrant authorizing the installation of a global positioning satellite tracking device on Jones's Jeep. The warrant carried a 10-day limit for installation within the District of Columbia; instead, the device was attached 11 days later, when the Jeep was parked in a Maryland parking lot. Jones's movements were monitored by GPS surveillance for 28 days. Evidence gained from the tracking was used to support his conviction for which, in light of his lengthy record, he received a sentence of life imprisonment. Jones appealed.[PAGEBREAK]

The Court of Appeals ordered suppression of evidence gained from the GPS surveillance, and the government appealed to the U.S. Supreme Court. Affirming the suppression order and the reversal of Jones's convictions, the Supreme Court has now held that the installation and monitoring of the GPS device constituted a Fourth Amendment "search." Absent a showing of a valid warrant or some recognized exception to justify this search, the evidence was properly suppressed, in the court's unanimous judgment (all nine justices agreed, in three separate opinions).

Here are salient passages from the majority opinion, written by Justice Antonin Scalia, who based his conclusions on the idea that a physical "trespass" (entry) by police that invades the "person, houses, papers and effects" covered by the Fourth Amendment (including vehicles), combined with an attempt to get information or to look for something, is a "search:"

"We hold that the government's installation of a GPS device on a target's vehicle, and its use of that device to monitor the vehicle's movements, constitutes a 'search,' Where, as here, the government obtains information by physically intruding on a constitutionally protected area, a search has undoubtedly occurred.

"Trespass alone does not qualify [as a search], but there must be conjoined with that what was present here: an attempt to find something or to obtain information. A trespass is not alone a search unless it is done to obtain information; and the obtaining of information is not alone a search unless it is achieved by such a trespass or invasion of privacy."

Although condemning the use of the GPS tracking in Jones, the court opined that if police had instead tracked Jones's movements by means of "mere visual observation," using "a large team of agents, multiple vehicles, and perhaps aerial assistance, our cases suggest that such visual observation is constitutionally permissible." In other words, it was the money-saving, manpower-saving, efficient use of technology to obtain the exact same information that rendered the surveillance of Jones unconstitutional. Go figure.

What Jones Said

The majority opinion in Jones said that when there is a physical intrusion by officials into the persons, houses, papers or effects of a suspect, coupled with an attempt to find something or gain information, a Fourth Amendment "search" occurs. This means that physical intrusion for other purposes does not necessarily constitute a search. It also means that getting information without physically invading the protected areas does not necessarily constitute a search. Both couplets must be present to invoke the Jones holding.

What Jones Did Not Say

Contrary to what much of the popular media have reported, the Jones decision did not say that a search warrant was necessarily required for GPS tracking. Under the basic Fourth Amendment rules, a warrantless search may be reasonable under a number of exceptions. For example, if a co-owner of a vehicle consents to GPS installation and tracking, the search would be reasonable. Vehicles belonging to persons on probation or parole search terms could presumably be tracked by GPS without a warrant. Likewise, your installation of a tracker on a bait car driven away by a thief would not violate the thief's constitutional rights.

However, in the absence of a recognized basis for a warrantless search, Jones does mean that a warrant must be obtained for installation and monitoring of a GPS tracker on a suspect's vehicle. Technology marches on, and criminals use it aggressively to great advantage, but law enforcement officers must use it cautiously, and sometimes only with judicial permission.

Devallis Rutledge is a former police officer and veteran prosecutor who currently serves as special counsel to the Los Angeles County district attorney. He is the author of 12 books, including "Investigative Constitutional Law."

Related:

SCOTUS: Police GPS Trackers Require Warrant

Surveillance Technology: An End to Stakeouts?