American snooping devices in space, at sea and on land, the computers that process their "take" and the analysts who study the results all combine to give the United States an extraordinary window on the Soviet Union's strategic programs. But is it good enough?

The answer to that question must lie in the eye of the beholder. "Good enough" is a political, not a technical category.

Adm. Stansfield Turner, for example, director of the CIA, has publicly reserved judgment on whether the new SALT II treaty can be "adequately verified." Privately, he has concluded that it can be, according to informed sources.

Turner, who sits atop the verification bureaucracy, reportedly reached this conclusion after considering what the Soviets could gain from the kind of cheating on SALT II that they might be able to get away with. The potential benefits were small, Turner decided, while the risks of being caught were high.

In other words, Turner has considered the laws of probability is reaching his final conclusion. Despite all the technology involved, in the end verification is a matter of judgment.

Amrom Katz, former chief of verification for the Arms Control and Disarmament Agency and an early pioneer in the field of space photography, is perhaps the most articulate proponent of a theory that the Soviets could cheat massively and get away with it.

In Katz' view, the American intelligence community has been guilty of "smugness, arrogance, complacence and overconfidence" in boasting of its abilities to monitor Soviet strategic programs.

Intelligence analysts should be thinking about what they can't see, not what they can, Katz argues. Their success in the past may be misleading, he says, since it is possible the Soviets have wanted the United States to observe their strategic programs.

The Soviets publish no figures on their rocket and submarine forces, he notes, yet they clearly expect the United States to take their strategic forces seriously. Have they perhaps been counting on American intelligence to establish the "credibility" of their forces?

What if the Soviets have also been building and deploying a secret missile force? Katz asks, one that they have wanted the United States to obreveal?

Might they some day announce to the United States that they had 500 extra missiles that they were about to fire at military targets in this country leaving intact their entire SALT-permitted arsenal?

"I'm not saying this is likely," Katz said recently. "It's bad enough that it's likely," - and not impossible.

Katz has reduced his skepticism to a single aphorism: "We have never found anything that the Soviets have effectively hidden." Katz is convinced that important things probably have been hidden.

In a recent debate on verification issues, William E. Colby, a former CIA director, dismissed Katz' scenarios as unfounded.

"It's a tautology to say that if we discover it they must have meant us to discover it," Colby said. He credited U.S. intelligence with the ability to detect any substantial cheating."I guarantee you we will know in advance" about any significant new developments in the Soviet strategic program, Colby said.

Another response from the intelligence community is that Soviet rockets are elaborate, sophisticated machines that require an array of supporting facilities and manpower that could not be successfully hidden on a large scale.

For example, the trucks that transport the Soviets' SS11 missile, long the backbone of their force, are 180 feet long and easily identified, according to an intelligence analyst.

A conventional missile silo takes months to build. A missile must be fueled, must have special command, control and communications facilities, must be protected by a security force - and all of these can be detected by U.S. snooping devices, according to working analysts and former officials like Colby and Herbert Scoville Jr., former deputy director of the CIA.

Sen. John H. Glenn Jr. (D-Ohio) has tried to establish himself as an expert on verification, a role many of his colleagues in the Senate appear willing to yield to the former astronaut.

In a series of public statements, Glenn has announced his belief that SALT II cannot be adequately verified with existing American eavesdropping technology.

In a recent interview, Glenn said he feared that the Soviets might be able, clandestinely, to add "three, four or five thousand deliverable nuclear warheads" to their forces without the United States detecting this change.

This is a real danger, Glenn said, because, without the listening posts the United States maintained in Iran, which picked up radio signals from Soviet rockets during test flights, the Soviets might secretly expand the warhead-carrying capacity of their rockets without detection.

As evidence, Glenn pointed to the recent tests of the Soviets' SS18 missile, in which the Soviets apparently experimented with decoy maneuvers suggesting that the SS18 might be able to dispense 12 independently targetable warheads during flight instead of the 10 permitted by SALT II. Why did they do that? Glenn asked. And if they did that, couldn't they go further and develop the capacity to carry 20 or 25 warheads on the giant SS18?

Administration officials respond that Glenn answered his own question. The United States caught the Soviets when they tried those decoy maneuvers, so any similar gambit would be detected in the future, they claim.

But the United States monitored those tests from Iran, Glenn replied, and without Iran that capability is lost.

Not so, administration officials counter. There were three tests of this kind, they say, and one or two - these sources refuse to be more precise - occurred after the Iranian bases were closed. "We 'saw' that decoy maneuver from somewhere else," one official said.

The principal deterrent to this kind of cheating, officials contend, is the need for full testing of such a complex strategic system. And full tests of an SS18 with 20 warheads would be detected by the radar on the Aleutian Islands, they say.

Administration officials acknowledge that there will be uncertainties in monitoring SALT II. Many of the conclusions reached by American intelligence analysts are net estimates that result from long study, discussion and sometimes debate.

Of the major provisions of SALT II, the one most difficult to monitor is the "new type definition." The two superpowers have agreed that each will be permitted to introduce only one new type of land-based intercontinental missile during the life of the treaty. A new type is defined as a rocket that is more than 5 percent larger or smaller than an existing rocket in any of its principal characteristics - weight, speed, payload and so forth.

Critics of the treaty contend that 5 percent is an arbitrary number that is much too precise, given the nature of monitoring technology. A rocket with a payload 8 or 9 percent larger than its predecessor could easily evade detection, some critics say.

Administration officials express confidence that the definition can be enforced. They grant that the Soviets might sneak in a few extra percentage points somewhere, but insist that this would be strategically insignificant.

The plan to put eavesdropping devices on U2 aircraft that could fly over Turkish airspace during tests from the Soviet base in Tyuratam, near Turkey, is intended to give the United States better intelligence for enforcing the new type definition. By the mid-1980s the United States hopes to have ultra-sophisticated "ferret" satellites in space that can pick up the radioed signals, or telemetry, from Soviet rocket tests.

Also at issue here is the Soviet ability to put those radio signals into code. Experts call this "encrypted telemetry." In a late addition to SALTT II, the Soviets reportedly agreed not to encrypt these messages if they are relevant to the limits set by SALT II.

Critics say this is meaningless, since it allows the Soviets to decide what is relevant. Administration sources disagree, saying the United States is so familiar with the patterns of Soviet telemetry that American analysts will be able to detect any encoding of SALT-related radio signals.

The Carter administration will have to acknowledge that some aspects of the new SALT agreements cannot be precisely monitored. One example is the limit set on the range of land-and sea-launched cruise missiles (600 miles), easily evaded just by adding extra fuel to these unmanned drones. But the United States will argue that this is a bigger problem for the Soviets than for the United States, since the United States if far ahead in modern cruise missile technology.

Like Turner, administration officials rely heavily on the argument that Soviet cheating would have to be cost-effective to be worth the risk of being caught by American technology, spies or even a Soviet defector.

Carter and other officials have spoken of the risks the Soviets would take by cheating. At a recent news conference, Carter said:

"The Soviets know that if we ever detect any violation of the SALT agreement, that that would be a basis on which to reject the treaty in its entirety. There would be a possible termination of the good relationships between our country and the Soviet Union on which detente is based. And it might very well escalate into a nuclear confrontation."

In the end the administration will rest its verification case on dilemma already described by Defense Secretary Harold Brown. With or without SALT II, Brown has observed, the United States will want to know everything it can find out about Soviet strategic weapons.

SALT II would ban "deliberate concealment" of each superpower's strategic weapons and interference with each other's "national means of detection" - satellites, listening posts and so on. It SALT II is rejected by the Senate, administration officials say, these aids to American verification will be lost.

But, they continue, the need for good information about Soviet programs would increase in the absence of SALT II's agreed limits on strategic forces.

"How will we verify a world without SALT?" as one official put it in a recent interview.

Critics say this is the wrong question - that the administration must show instead how it can verify this treaty.