PITTSBURGH — ELECTRONIC eavesdropping has advanced to the point where police can sit in a van outside a house and tell what a person is typing on a computer inside.
It's that kind of capability President Clinton now wants to see used more often as he moves to expand the surveillance powers of law-enforcement agencies.
The catalyst for the Clinton proposal is last month's terrorist bombing in Oklahoma City. But Clinton's legislative response to the blast has its skeptics. Civil-liberties groups, and even some Republicans say that the administration's proposals have little to do with terrorism and could broaden police powers unnecessarily. The proposal comes against the backdrop of an increase in electronic surveillance nationwide.
Last year, for example, US courts granted law-enforcement agencies a record 1,154 electronic-surveillance orders, according to the Administrative Office of the United States Courts. The total was nearly 200 more than in 1993, which also set a record.
But police do not appear to be carrying out aggressive campaigns against specific groups -- as they did against anti-Vietnam War protesters and the Black Panthers 25 years ago, though their ability to conduct surveillance is broader and more powerful today.
Instead, law-enforcement agencies have begun what former Massachusetts Institute of Technology sociology professor Gary Marx calls ''the new surveillance.''
''The character of surveillance has changed,'' agrees Marc Rotenberg, director of the Electronic Privacy Information Center (EPIC), a public-interest research group in Washington, D.C.
''What grew up in the [former FBI Director J. Edgar] Hoover years and reached its apex in the '60s and early '70s was the targeted approach, where groups were singled out.''
But today, he says, ''Through technology and the growing power of law enforcement generally, we have routinized the practice of surveillance. We have been able to bring under the government's eye a much wider slice of the population.''
Law enforcement's use of other technologies also appears on the rise. Authorities are linking together their computerized databases for faster access to information. And increasingly sensitive devices -- night scopes, parabolic microphones, long-range telephoto lenses -- continue to enable access behind closed doors.
''The new surveillance,'' Professor Marx wrote in his book ''Undercover,'' ''transcends distance, darkness, and physical barriers.... Physical limitations and, to some extent, human inefficiency have lost their usefulness as unplanned protectors of liberty.''
A technology called forward-looking infrared radar, for example, can ''look'' through walls and ceilings to detect grow lights for plants, says Mr. Rotenberg. If police suspect someone is growing marijuana in their home and use the radar, is it good detective work or an invasion of privacy?
Should these technologies require a warrant? Federal courts have reached different answers, he says, and so far the US Supreme Court has not stepped in.
The shock of last month's Oklahoma City bombing has pushed these privacy concerns into the background for now. The Clinton administration last week put forward its plan that, among other things, would relax some restrictions on electronic surveillance. The proposals include:
* Fewer restrictions on ''pen registers'' and ''trap and trace'' devices.
These technologies allow agents to track the telephone numbers a suspect is dialing as well as the phone numbers of the people calling him.
When federal agents want to use these devices in ''national security'' cases, US courts currently require more compelling proof of a threat than in routine criminal cases. Clinton's proposal would drop the higher standard.
* Fewer limits on introducing surveillance evidence in court.
Current legislation requires that police follow strict rules before the evidence obtained for wiretapping can be used in court. The Clinton proposal would eliminate those limits unless investigators acted in bad faith.
* Larger list of felonies justifying electronic surveillance.
Current law restricts the number of felonies that justify wiretapping. The Clinton proposal would add any terrorism-related or explosives felonies to the list.
However, the US Attorney General, a deputy, or an assistant would have to certify that domestic or international terrorists were or might have been involved. Emergency wiretap orders, which cut through much of the usual paperwork, could also be justified on the basis of terrorism.
* Expanded use of roving wiretaps.
The Fourth Amendment of the Constitution protects people from ''unreasonable searches and seizures'' unless authorities obtained a warrant ''describing the place to be searched.''
But in 1986, Congress allowed a small exception, so that police could wiretap organized-crime suspects who moved from phone to phone or used other evasive tactics. The Clinton proposal would open the door wider, allowing roving wiretaps if a judge found that specifying a place for the surveillance was ''not practical.''
* Funding telephone companies that make digital networks capable of being wiretapped.
President Clinton already signed a digital-telephone bill last year. But without funding it, the administration in essence was giving telephone companies up to four years to comply.
The new Clinton proposal speeds up the process by providing up to $485 million in funding over the next three fiscal years. To raise the money, a 40 percent surcharge will be added on all civil penalties levied by federal agencies.
The White House is pushing for quick action. ''There's real bipartisan interest in this and there's considerable overlap between the president's bill and the Republicans' bill,'' says Bruce Reed, White House adviser on counter-terrorism.
''Our experience has been that the more people study the details, the less concerns they have about the proposals we have put forward, which certainly don't break new constitutional ground.''
But civil-liberties and privacy groups are skeptical. ''Most of what's being asked for here is completely unrelated to any problems the FBI has discussed with respect to the problem'' of terrorism, says Daniel Weitzner, deputy director of the Center for Democracy and Technology, a nonprofit civil-liberties group in Washington.
For example, most wire-tap orders concern drugs, not terrorism. The last time a state or federal law-enforcement agency asked for electronic surveillance authority for an arson, explosives, or weapons case was 1988. Also, there is little evidence that more wiretapping increases convictions.
An EPIC study found that even though the amount of wiretapping has increased markedly, the number of incriminating conversations captured by investigators has remained relatively stable since the 1970s. Last year, according to the study, prosecutors' deemed only 17 percent of intercepted conversations ''incriminating.''
The US has swung widely back and forth in its attempts to balance the right to privacy with the needs of police enforcement.
''They're always in tension,'' says Steven Barkan, a sociology professor at the University of Maine in Orono. ''The more freedom you want, the less crime control you have. The more crime control you have, the less freedom you have.''