IF CONGRESS WERE faced with a single bill to provide various degrees of antitrust immunity to doctors, attorneys, engineers, accountants, dairies, beer wholesalers, football teams and the shipping industry, the measure would rightly be condemned.

It would be a sweeping effort to undermine laws designed to make sure consumers have wider choice, lower prices and quality products and services.

Yet, remarkably, Congress is seriously considering an assortment of bills to carve out special antitrust immunities for each of these interests.

Antitrust is, as the Supreme Court has put it, the "charter of economic liberty aimed at preserving free and unfettered competition as the rule of trade." Congress and the courts, therefore, generally have been hesitant to exempt industries or professions from the rigors of competition without compelling evidence that competition won't work.

Indeed, changes in antitrust laws have been designed mostly to strengthen and expand the role of competition rather than provide single-industry exemptions.

But things began to change in 1981. That was when Congress passed a bill partially exempting sofe drink bottlers from antitrust. At the time, some predicted that their success would open a special-exemption Pandora's Box. They were right.

Over the past few years, special interests have waged a powerful if little-noticed campaign to make the most fundamental and damaging changes in antitrust law in history. They have misled Congress into believing that eliminating antitrust is consonant with the popular drive to cut government regulation.

However, it is ludicrous to characterize antitrust as "regulation." In truth, it is just the opposite. It seeks to eliminate the harmful effects of agreements among firms to limit or destroy competition. Such agreements, of course, amount to private sector "regulation" and have the same undesirable effects as government regulation.

Strong, vigorously and uniformly enforced antitrust laws are the best means to achieve a truly competitive environment in the deregulated economy of the 1980s.

Despite the misleading arguments, the special-interest assault on antitrust is making remarkable progress. Why? One answer may be the sheer volume of money being spent to achieve the goal.

The emergence of business and professional political action committees as powerful voices in the legislative arena has drowned out the voices of consumer and other groups.

The American Medical Association, for example, has the single biggest spending professional PAC in the nation, known as AMPAC. According to the Federal Election Commission, AMPAC made over $500,000 in political contributions from January 1981 to March 1982. Perhaps more revealing is the fact that 97 percent of congressional sponsors of a measure to eliminate the Federal Trade Commission's antitrust (and consumer-protection) authority over doctors (and other so-called "state-regulated professionals") have received a total of $1.1 million since 1979.

Clearly, getting the FTC out of the antitrust business has been one of the AMA's highest priorities.

The AMA has tried to argue that FTC "regulation" of doctors has interfered with professional judgment involving patient care. Does it have a case? Consider the kind of behavior the FTC has challenged.

In one case, a group of doctors in an isolated Texas town threatened to boycott the local hospital's emergency room if the hospital hired a new doctor who might compete with the existing group. The FTC prohibited this conduct' Would the patients in the town be better off without such FTC "regulation"?

Similarly, a group of doctors boycotted a Blue Shield plan that wouldn't raise fee levels to the amounts demanded by the physicians. The FTC barred the boycott. Did this interfere with professional judgments about patient care?

Clearly, these actions by physicians had little or no relationship to medical standards, involving only the business aspects of the profession. It is not the FTC's antitrust interpretation that bothers the AMA; it is the application of free enterprise competition rules in general, which the doctors find offensive.

In fact, a recent AMA resolution to try to stop all federal and state antitrust oversight of the medical profession -- not just the FTC's -- reveals the not-so-hidden motive of its legislative assault.

Another group clamoring for special treatment is the shipping industry. It is seeking a total antitrust exemption, even though the entire thrust of recent congressional action involving transportation industries in recent years has been to promote competition, not eliminate it.

Proponents argue that the industry is in such bad financial shape that protection from competition is necessary to keep the U.S. merchant marine from going out of business. But a recent General Accounting Office report pointed out that "the U.S. flag fleet in not in a state of general distress significant enough to justify a major revision" of the law.

The beer industry has also paid a visit to Congress this year. It is seeking support for a bill that would grant local monopolies to beer whole salers. The measure would do nothing except raise the price of beer. Not surprisingly, the industry argues that if soft drink bottlers received an exemption, so should the beer distributors.

If that were not enough, the Senate is currently considering a bill that would reduce the liability of a handful of price fixers after the firms have gone to trial and lost. It is one thing for powerful groups to exercise their influence to change the law for the future; it is quite another to change the law after it has been broken.

The harm to consumers in this situation is not the loss of some abstract benefits flowing from competition.

Hundreds of thousands of businesses and millions of consumers have already paid more than $1 billion in price-fixed oVercharges on corrugated cardboard, polywood, and textile products. The losing firms, however, are attempting to make Congress a court of last resort for lawbreakers. Remarkably, Cogress may give in to these outrageous pleas.

It is, perhaps, no longer shocking that big business has inordinate power to accomplish its special legislative agenda. We have become numb to the repeated pummeling of consumers by industries united in their aim of achieving protection from the law.

But it should be shocking that these profound changes in national antitrust policy may be adopted without a single congressional hearing.

Antitrust is not a "liberal" or "conservative" doctrine. It is simply an acknowledgement that for the free enterprise system to work well, it is necessary to have a "cop on the beat" to police cheating on the competitive process.

As is true with other criminal statutes, it is unwise and contrary to our basic democratic principles to create classes of individuals or businesses who are above or outside the law. And Congress should certainly not allow the denigration of law and the legislative process by creating a patchwork of exemptions for those who can afford to accomplish their selfish purposes.