In 1999, in the midst of alleged leaks of nuclear weapons information from his department's national laboratories, the secretary of energy, Bill Richardson, set out to show that he could be "tough" on national security matters. He sought congressional funding for a wide-ranging polygraph program to cover all employees with high-level clearances -- about 15,000 people in all.

Congress agreed -- despite the absence of any evidence that polygraphs have ever detected a spy operating anywhere in the U.S. government. But Sen. Jeff Bingaman (D-N.M.) managed to get the Senate to stipulate two important conditions -- first, that the National Academy of Sciences (NAS) review the medical and scientific literature to determine whether use of polygraph tests for screening was in any way worthwhile and, second, that the secretary report back to Congress after the NAS report was completed.

Late last year the NAS published its findings. It determined that the polygraph was not a worthless tool -- indeed, that it was much worse than worthless. The report said that "available evidence indicates that polygraph testing as currently used has extremely serious limitations . . . if the intent is both to identify security risks and protect valued employees." The NAS panel, made up of internationally respected psychologists and statisticians, further determined that the test was so nonspecific that even if the polygraphers managed to finally uncover their first spy, at least 100 innocent laboratory employees would have their clearances yanked because of the "false positives" inherent in the test. The NAS concluded: "Polygraph testing yields an unacceptable choice . . . between too many loyal employees falsely judged deceptive and too many major security threats left undetected. Its accuracy . . . is insufficient to justify reliance on its use in employee security screening in federal agencies." It doesn't get much clearer than that.

Spencer Abraham, the current energy secretary, was faced with a dilemma: If he did the right thing by openly recommending that Congress trash his predecessor's polygraph program, he would embarrass his counterparts in the CIA and the Defense Department, where faith in the polygraph long ago reached cult status. If he kept the polygraphs, he would do so in the face of the academy's clear rejection and more than 60 years of evidence that they waste taxpayers' money while destroying the careers and lives of countless loyal Americans.

Abraham opted instead for a third course. In a memo to the national laboratory directors in late March, the secretary said he had decided to "defer" his decision on polygraphs until "after hostilities in Iraq had ended." That wasn't quite true. Just two weeks later, an official Energy Department "proposed rule" appeared in the Federal Register, in which the secretary gave it as his opinion that "DOE [the Energy Department] does not believe that the issues that the NAS has raised about the polygraph's accuracy are sufficient to warrant a decision by DOE to abandon it as a screening tool. Doing so would mean that DOE would be giving up a tool that, while far from perfect, will help identify some individuals who should not be given access to classified data, materials, or information."

There is supposedly an opportunity for the public to comment on the Energy Department's proposal to do nothing. But there is little reason to believe the department has any intention of listening, given its willingness to dismiss all credible science on the issue without any explanation.

The aftermath of this episode of bureaucratic bungling is even worse. Since the secretary displayed his studied ignorance, the department has been faced with yet another polygraph embarrassment: William Cleveland Jr., head of counterintelligence at the Lawrence Livermore National Laboratory (and a retired FBI agent), stands accused of a reckless tryst with Katrina Leung, recently indicted as a Chinese double agent. During that time, the FBI paid her $1.7 million to spy on Beijing.

Cleveland asserts that he warned another FBI counterintelligence agent and Leung's handler, James J. Smith, about her. Smith, it turns out, was having an affair with Leung at the same time. Cleveland passed his DOE polygraph, even though during his examinations he was asked if he had "unauthorized contact with representatives of a foreign government." Smith has been arrested, but the damage is done: Leung copied their secret documents, probably sending them on to her friends in the Ministry of State Security in China. So much for "identifying some individuals who should not be given access to classified data, materials, or information."

Unfortunately, there is nothing new here. Two years ago I wrote a piece in the science magazine Skeptical Inquirer recounting the multiple failures and ignoble history of the polygraph, and the mindless faith invested in it by presidents, CIA and FBI directors, police departments and other people who ought to know better. Shortly thereafter a letter to the editor arrived, stating: "In my experience with the polygraph, as user and subject, its junk science does provide an important but discreditable service for lazy and timid national security managers (also known as a species of bureaucrat). There's a lot at stake for the bureaucrat. Faced with the prospect of excruciating hard work, considerable expense and agonizingly difficult choices, the [polygraph] offers an attractive refuge from responsibility. Like handing fate to the stars . . . bureaucrats can abandon their duties and responsibilities to junk scientists and interrogators masquerading as technicians."

The correspondent, writing from prison, was Aldrich Ames, perhaps the most damaging spy in all of U.S. history. Over Ames's 30-year career -- the last decade of which was spent as a mole within the CIA ratting on his own agents -- more than a dozen U.S. intelligence operatives in Moscow and elsewhere perished, while Mr. Ames netted a cool $3 million, courtesy of the KGB.

Meanwhile, he passed his CIA polygraph every five years.

The writer is a senior scientist with the Center for National Security and Arms Control at Sandia National Laboratories. The views here are his own.