I have never before been at odds with the views of Ambassador Jeane Kirkpatrick. But I must take issue with her categoric rejection of polygraph examinations ("Polygraphs? No." op-ed, Dec. 29) as a means of deterring and detecting spies. The analysis underpinning her conclusion was short on fact, long on assertion.

Kirkpatrick confuses the device known as the "polygraph" with the examination process in reaching a verdict of unreliability. The polygraph simply records three or more physiological reactions, as one input to a trained examiner who makes provisional judgments of truth or deception in the context of extended dialogue, before and after the recording, with the individuals concerned. Humans are not infallible. However, to cite the American Foreign Service Association as authority for unreliability of the process is as bereft of credibility as relying only on the American Polygraph Association in rebuttal.

A wide range of professional organizations and scientists have pursued the subject exhaustively for many years. Assessments vary, but the weight of evidence is that under regulated conditions the combination of electro-mechanical instrument and qualified examiner is a very useful investigative tool. On the basis of its intensive research, the National Security Agency concludes that, conducted by experienced personnel in a setting that assures quality control, the reliability of the process is 90 to 95 percent. That's far from perfect; and for that reason no action can be taken against any government employee solely on the basis of the polygraph examination.

Polygraphers face their greatest challenge in working across linguistic and cultural barriers. The case of Larry Wu-Tai Chin is illustrative. There's a report circulating, which the aforementioned State Department affiliate saw fit to repeat without checking, that Chin passed numerous polygraph tests. Not so. He was administered a single examination and that in 1970 before the establishment of the sophisticated control procedures in effect today.

Actually, the better gauge of reliability -- and therefore utility -- of the polygraph examination is comparison with other investigative techniques. In the experience of the Central Intelligence Agency and National Security Agency, the examination has repeatedly produced information relevant to an individual's trustworthiness that failed to surface in background investigations or by other means. It is unrealistic to expect background investigations -- on which Kirkpatrick would place full reliance -- to turn up evidence of espionage. Character flaws, probably; vulnerability to blackmail, perhaps; but intent to commit espionage, no. Yet, there are numerous cases on record where the polygraph examination has unmasked persons seeking employment for the purpose of espionage.

Moreover, one must take heed of the testimony of convicted spies such as Christopher Boyce and William Bell that they would not have even considered espionage if they had had to undergo a periodic polygraph examination. And why did David Barnett, Edward Howard and Ronald Pelton allegedly not become spies until after they had left their respective agencies and their value to the KGB was dramatically reduced?

All this said, Kirkpatrick would apparently object to polygraph examinations for counter-espionage purposes even if they were adjudged to be errorless. Her overriding concern is that examinations of even limited scope (confined to such questions as "Are you a spy?") given to a limited community (say, 1 percent of those holding security clearances) would represent a gross intrusion upon the privacy of government employees, leading to the "institutionalization of distrust." That perception is baffling. Certaly the conduct of background investigations, whose pervasiveness varies with the sensitivity of the position to be occupied, is an intrustion upon privacy; yet employees are routinely asked to consent thereto. Certainly, too, the reporting of personal information that may have security significance is an intrusion upon the individual concerned; yet commanders and supervisors are required to tender such reports on their subordinates.

Access to classified information is, after all, a privilege -- not a right. And, given its primary responsibility for ensuring that its citizens and institutions survive in freedom, our government must have the requisite means to assess on a continuing basis those to whom it entrusts the secrets sought by nations with hostile interests.

My entire adult life has been spent in the service of the United States, on and off the battlefield, with the West Point motto my constant lodestar. Rank and record notwithstanding, I deem it mete and proper for my government to ask me to confirm, via a limited polygraph examination, that I have but one allegiance. It seems only prudent to do so before giving me the capability, should I wish to exploit it, to do our nation incalculable harm. Moreover, I am ready to be the first volunteer to set the pattern for sergeants and secretaries, communicators and engineers who will share the capability.

Prior to 1983, the polygraph had never been used for any purpose in the United Kingdom. In the wake of an espionage case involving convicted spy Jeffrey Prime that rocked Britain, the government concluded that it had no choice but to institute polygraph examinations of limited counter-intelligence scope. Prime Minister Thatcher personally addressed the Parliament to explain this break with tradition:

"The polygraph is the only measure of which it could be said with any confidence that it would have protected (government secrets) from Prime's treachery, either because it would have deterred him from applying to join or would have exposed him in the course of examination. The (government) recognizes that a polygraph examination would be seen by some as an unwarranted invasion of their privacy, but we are dealing with matters of the highest national security, and those who have access to the nation's most sensitive secrets must expect to be subject to the most rigorous vetting procedures."

No one could have put it better.