AS HARVARD ATHLETES returned this fall and signed in at UHS for their physicals and signed out their equipment and signed forms telling the NCAA they didn't accept money and nice cars from recruiters and signed another form giving the NCAA the right to possibly test them for drug use and--wait a second.

All of a sudden it is no longer enough for college athletes to affirm they will play by the rules; now they have to allow the NCAA access to their bodies.

The same would now be true of federal government employees had a Federal District Court ruling not preempted President Reagan's executive order of September 15, to implement drug testing of federal employees.

Forget the legal niceties of how such "unwarranted searches" may violate civil rights. The judge could have ruled the other way. Consider the case of another screening issue in which the Justice Department decided last June that those who test positive for the AIDS virus are not protected under civil rights law from discrimination by their employers.

The difference in rulings points to the power of societal assumptions, rather than strictly legal logic, in judicial decisions. There was a consistent body of judicial reasoning and precedent that yielded each of the contradictory rulings. The difference, however, was an assumption--in this case the stigma attached to a certain disease--which swayed the calm courtroom logic of the law.

THERE IS A parallel between those who may carry a virus and those who may carry a drug in their bodies. In both cases testing is justified by placing the perceived welfare of the community over the right of an individual to be free from invasions of his person. The unreliability of drug tests and the improbability of transmitting AIDS shows the rationale of screening to be merely the face of power.

A study carried out last spring by the Federal Centers for Disease Control (CDC) found that the accuracy of urine tests for substances like cocaine varied tremendously from laboratory to laboratory. More than nine out of 10 labs failed the CDC's standards, and understandably the CDC has declared a "crisis in drug testing."

While a few percentage points in test accuracy entail the prospect of tens of thousands of false positive results and falsely labelled individuals, screening suffers from another kind of subjectivity. It is politically easiest to propose or implement screening of groups that are already defined and over which the government or an employer already has direct power--as in, for instance, the AIDS testing of ROTC cadets, the drug testing of federal employees or the testing of the employees of an estimated one quarter of the nation's largest private firms. There is no medical reason for such choices, and the allegedly technical screening reveals itself as a power relationship between testers and tested.

Likewise, anybody who calls for drug testing ought to consider the following question. What will you tell those who test positive and those who test negative? Those who test positive would undoubtedly be informed of the dangers to their own health and the potential for losing their jobs. Meanwhile, those who test negative--surprise!--would be informed of the dangers to their own health and the potential for losing their jobs if they had used the drug. Because each is being told essentially the same thing, the hidden motivation of the test emerges as an intimidation tactic.

Testing, for drugs or AIDS, becomes yet another strategy of intimidation in the power dynamic between employers and employees. There is no call for alcohol testing at business lunches or meetings between high-level diplomats. The logic of screening makes the body a site for a conflict of interests.

THE REAGAN Administration's crusade for the screening of all federal employees for drug abuse is a policy that can be cited for absurdity before citing it as offending against basic civil rights. Could they not fire that mythic crack-smoking federal employee based on a far simpler index than drug levels in blood--like job performance?

Why federal employees? They're an easy target. By implementing a screening process at a pre-existing checkpoint--in this case, people who need some form of security clearance--the government reinforces an existing power dynamic. Not only can they be screened more easily in a technical sense, but the drug test begins to look like just another item on a list of criteria that an individual must meet.

As screening becomes just another innocuous requirement for getting a job or participating in athletics, institutions gain a whole new dimension of power over individuals. Access to that kind of knowledge about a population creates a whole new network of social controls. Power is no longer in a white-domed building in Washington, it reaches out and takes a blood sample.