Nine years ago, in the sleepy seaside village of Florence, Oregon, a member of the Oregon National Guard pointed a thermal imaging device, the Agema 210, at a frumpy triplex. For a few weeks, agents routinely had been casing the house, looking for evidence that marijuana was being grown and sold there.

With help from the Agema 210, the agents discovered two "hot spots"--areas in the house that were unnaturally warm. They concluded that the residents were in fact using heat lamps to grow pot. Eventually, that discovery led to the residents' arrest and incarceration.

But what the agents didn't expect was that their seemingly simple action--using spy technology to build a case against a small time pot grower--would set in motion a series of legal cases that may alter the border between what police throughout the U.S. may and may not do.

After limping through the federal courts, on Tuesday, February 20, the so-called Kyllo case will reach the U.S. Supreme Court. The Kyllo case, to be argued by local defense attorney Ken Lerner, stands at the forefront of an increasingly desperate debate over the Fourth Amendment--the Constitutional doctrine that sets guidelines for police searches. Drafted to protect normal citizens from police kicking down their front doors, the flip side of the Fourth Amendment is a person's expectation of privacy.

"There had been a bright line drawn around the home," says David Fidanque, executive director of the Oregon affiliate of the ACLU, referring to the traditional legal notion that a man's home is his castle and the police cannot enter without permission. But, over the past few decades, as technology has outpaced legal protocols, that privacy has been left up for grabs.

With each advance in technology--from wiretaps in the 1920s to monitoring cell phone conversations in the 1990s--the Supreme Court has tended to whittle away an individual's amount of privacy in his home or car, points out Fidanque. "It is dangerous," he adds. "They are becoming more and more intrusive."

The opinion from the Supreme Court on the Kyllo case--not expected until early summer--will mark how true George Orwell's predictions for an intrusive police state have become, as well as open or close the door for further police intrusions.

In Portland as well as around the country, there is an increasing sense that police are using technology to invade privacy. Two weeks ago in Florida, the FBI secretly photographed Super Bowl spectators as they entered Raymond James Stadium and compared those photos against a database of known terrorists. In addition, applications for wiretaps by the FBI have continued to increase annually. In Portland, concerned that police and FBI agents are photographing their activities, a coalition of political activists have formed a group to counter police spying.

Although the distinct issues between Fourth Amendment cases may differ--from the use of thermal imaging devices to roadblocks to check for drugs--they all lead back to the same premise: that Americans demand and expect a certain degree of privacy, whether at home or in their cars.

Earlier in this Supreme Court session, the notion of privacy narrowly escaped further winnowing when the Supreme Court decided that federal agents may not board a Greyhound bus and feel soft-sided suitcases for drug paraphernalia. In a second case, the justices determined that police may not set up roadblocks to randomly test drivers for drug use.

In practice though, Portland police are reaching further into individuals' privacy, according to a number of criminal defense attorneys and legal experts. Of the 260 complaints filed annually with Portland Police Bureau for misconduct, nearly one-third stem from disputes over the procedure used to search a vehicle or home. In response to such concerns, the Oregon Criminal Defense Lawyers Association has introduced to the state legislature SB 142, a proposed law to require that police clearly explain to a motorist that he need not consent to a search of his or her vehicle. The bill will be debated this legislative session.