VIETNAM VETERANS have so far been unable to get what should be theirs by right: serious attention from the Pentagon and the Veterans Administration to their claims of having been harmed by exposure to the defoliant Agent Orange. It is a sorry spectacle.

The Air Force's study of its men who were exposed was supposed to have begun last fall. It still hasn't begun. And in a review published this past week, a panel of experts from the National Academy of Sciences concluded that the study plan had "major weaknesses that would preclude attainment of the stated study goals" and that would "prevent the researches from identifying even a moderately strong effect" of exposure to Agent Orange. The reviewers concluded that the number of men to be studied was too small and that the planned medical examinations focused on too many possible effects but none of them in sufficient detail.

Were it not for traditional interservice rivalries and bureaucratic inertia, the key failing could be easily corrected, for in addition to the 1,200 exposed Air Force personnel, a much larger number of Army and Marine men were exposed to the herbicide. The Marines can identify about 6,000 men who were in areas sprayed with Agent Orange on the same day as the spraying. Unfortunately, the Air Force has so far indicated no willingness to include other services' men in its study.

The National Academy panel also felt that it was "inappropriate" for the Air Force or the Department of Defense to do this study, and strongly recommended that one or the other should provide funding for another group to design and conduct a study. In its response, the Air Force has announced that the academy's recommendations will be referred to yet another review group for "an examination of how the study should be conducted and by whom."

In other words, after more than a year of work, the Air Force is back to square one. Meanwhile, the Veterans Administration -- under a congressional directive -- has been slowly and reluctantly moving toward a study of its own, which is likely to duplicate or contradict the Air Force study.

While all of this is happening -- or not happening -- the people being hurt are the vets, some of whom are desperately afraid of increased risks of cancer or of fathering deformed children. There is a logical way to straighten things out. Instead of two studies, each performed by an involved and potentially biased agency, there should be a single large study, funded by the government, but carried out by the best possible outside experts. With quick congressional action, it could be under way within a few months.