UFOs are like untainted politicians -- you hear about them from time to time, but you never actually see one.

OK, that's a bit harsh -- people have been seeing or otherwise detecting UFO's worldwide in great numbers since the late '40s. In the last half of the 19th century there were sporadic reports by people claiming to have seen bizarre "airships," which they figured were some new-fangled hot-air balloons -- balloons providing their only frame of experience for airborne technologies.

Investigations involving large series of sightings consistently succeed in plausibly identifying or explaining the causes in about 90 percent of UFO reports. There are a few hoaxes, a small number of mentally ill people, and lots of misidentifications of manmade objects or natural phenomena.

But it's that remaining 10 percent that's problematic. Many of these sightings are reported by people with established credibility and impeccable credentials -- trained military observers and radar operators, commercial airline pilots, law enforcement personnel. Not that such people are immune to misinterpretation or flights of imagination. But they usually have been around long enough to become skilled in the identification of prosaic objects and unusual atmospheric phenomena.

That UFOs "exist" is beyond dispute -- that is, many people have seen aerial phenomena which possess characteristics of actual physical objects; these objects behave in a manner consistent with flight; and the witnesses cannot identify them.

What remains very much in dispute is the significance of these objects. Are they heretofore-undiscovered natural phenomena? Are they top-secret highly advanced government projects? Or is there even a possibility they could represent a vastly superior technology developed by an extraterrestrial (or future terrestrial) culture?

The spectrum of opinion on this issue has extremists at both ends. There is no dearth of "True Believers." In the 1950s, there arose a highly-visible small group of supposed UFO witnesses called "Contactees." They usually claimed to have been approached by UFO occupants, often radiant blond Caucasians in luminous clothing, with exotic names from improbable planets, bearing messages of peace and good will, along with standard warnings against fussing amongst ourselves. So far as I know, every one of these Contactees' stories was conclusively debunked as outright fabrication or mental imbalance.

Scarcely more credible UFO stories still circulate, and there are plenty of credulous people who swallow them uncritically.

On the other end of the spectrum are the professional debunkers. These are often self-proclaimed skeptics who claim to take a dispassionate, objective stance while evaluating UFO reports. In reality, they are primarily seeking to validate their own firmly-established preconceptions: "(extraterrestrial) UFOs can't exist, so they don't." Their attempts to debunk any and all sightings can involve the most absurd or irrelevant "explanations" one can imagine. The arguments commonly fail to incorporate or even acknowledge the specific details of witness reports, including radar imaging, simultaneous air, ground, and radar sightings or multiple skilled witnesses at close range.

Patently absurd rationalizations or dismissals are no more useful than UFO kooks' starry-eyed knee-jerk acceptance.

If you've read some of my other columns, you might suspect that I consider myself a skeptic, one who does not easily accept assertions which are not based to some degree on substantive evidence or testable proposals. But I do not lump the UFO phenomenon into the same category as ghosts, astrology and other so-called "occult" or pseudoscientific beliefs. This automatically puts me at odds with many others in the skeptical community. I console myself that scientific agnosticism has a rich provenance.

It is clear the government knows more about UFO's than they are telling us. Relax, this isn't (necessarily) a matter of rampant conspiracies. There could be legitimate reasons for government-sponsored debunking and ridicule.

During the Cold War, UFO "waves" generated large numbers of phone calls from the public to law enforcement and military switchboards, enough to swamp them. Most military personnel were aware of "hard" UFO encounters, many of which had occurred at or over military bases and nuclear facilities. The result could have been a delayed or failed response to actual hostile enemy (Soviet) incursions. The government also worried about "public hysteria" that would render us vulnerable to enemy psychological warfare. (Today, there is less fear of panic in the streets than of disrupting financial, governing and religious institutions, should evidence of visitation by highly-advanced alien cultures be confirmed.)

Thus, in 1953, the Robertson Panel Report to the Pentagon and CIA recommended that a systematic policy of publicly debunking UFO reports be implemented -- and it was. (The report was only declassified in 1975 after a FOIA request.) Not only were purported sightings explained away and dismissed, sometimes without investigation, but witnesses were ridiculed, accused of being psychotic, or charged with self-serving publicity seeking. Military personnel and commercial pilots were intimidated by threats of being grounded or dismissed if they disclosed UFO encounters to the public.

The debunking policy was undeniably successful, and report volumes plummeted. Only recently have former flight controllers, military pilots, missile-tenders and nuclear weapons personnel begun to come forward in numbers, driven by conscience to risk personal penalties in order to let the public know.

Throughout the past 60 years, the government has continued to silently but systematically acquire and compile voluminous UFO-related evidence. In my next few columns, I'll share for the first time in writing a baffling 1976 case study I personally investigated.

Jon Hauxwell, MD, is a retired family physician who grew up in Stockton and now lives outside Hays.

hauxwell@ruraltel.net