LAST DECEMBER, as the White House Cabinet Council on Commerce and Trade argued over requests from the American textile industry to stop any loosening of limits on imports from Taiwan and China, Chief of Staff James A. Baker III pulled out a copy of a 1981 letter from Ronald Reagan to his 1980 supporter, Sen. Strom Thurmond (R-S.C.). In the letter, Reagan promised to help South Carolina textile mills against foreign competition.

After nearly a year of intense negotiations over restrictions on textile imports -- a protectionist concept against Reagan's free trade ideology -- two White House aides said the letter killed the council debate cold. What had been a policy debate involving U.S.-Chinese trade relations became a discussion of how the White House could save any smidgen of antiprotectionist principle while giving the textile industry what Reagan had promised.

In the end, southern textile interests got nearly everything they wanted. White House aides explained the decision as an act of "loyalty" to a political supporter -- no matter that it defied Reagan's own oft-repeated principle of encouraging free trade or that it endangered U.S.-Chinese relations.

Just a month later, at the informal kickoff of his reelection campaign, Ronald Reagan made a stem-winder of a political speech in Atlanta. Reagan used the occasion to lambaste his Democratic rivals for pandering to special interest groups:

"Today we see candidates trying to buy support by telling people what the country will do for them and making promises to interest groups. I don't believe the American people can be bought with promises from the federal treasury and with schemes which politicians claim will be paid by someone else."

Reagan loves to depict the Democrats as the captives of special interests. But, in fact, the president has been doing a great deal for special interests of his own -- the groups that benefit the most from his advocacy of tax cuts and deregulation and his stands against abortion and gun control.

But Reagan -- unlike the Democrats -- seems to be immune to criticism on this point.

Exit polls show that many voters consider Walter F. Mondale a captive of special interests, but such accusations just don't seem to stick to Reagan.

After watching Reagan up close for nearly two years, I've come to the opinion that he gets away with his brand of catering to special interests because, as a master politican, Reagan successfully creates the illusion that he is a man above politics -- a man of principle, a servant only to his conservative ideology, not to any single faction of voters.

But it does seem to me that Reagan's policies cater to interest groups as much as Mondale's public pronouncements do. Mondale pleases union members, feminists, blacks and environmentalists; Reagan delights businessmen, wealthy taxpayers, promoters of prayer in school and the antigun-control lobby.

There something of a qualitative difference between Reagan and Mondale. In order to draw on union resources, for example, Mondale supports specific labor goals, such as a domestic content bill. Reagan has no need for such specific appeals because he already has the monied support of businesses that welcome his tax cuts.

All he needs is the votes of the ideologically committed, and he gets those through broad statements -- "America Is Back." If he does mention specifics -- speaking in agonizing tones about the pain allegedly felt by aborted fetuses, for example -- it is in the course of presenting a general view of the society. He wants his listeners to feel he represents a return to a church-going, anticommunist world power -- America in its glorious past.

Yet in fact, if the polls are to be believed, many of Reagan's special constituencies and causes are much less popular with the general population than are Mondale's. And Reagan delivers to them, even if he advertises them less as a payoff than as an act of loyality to his supporters, like Thurmond. And who can say loyalty is anything less than a virtue?

Consider the National Rifle Association and Reagan. Here is a classic example of a special interest group whose concerns are clearly out of step with those of most Americans. A 1983 Gallup Poll showed 59 percent of Americans wanting more strict handgun controls. Even among gun owners, 47 percent said they wanted more strict gun controls.

Yet Ronald Reagan has staunchly supported the NRA and virtually its entire program. The NRA's program includes opposition to attempts in Congress to ban the sale of "armor piercing" bullets. The nation's policemen avidly support such a ban because the bullets, which serve no legitimate purpose, can penetrate policemen's bulletproof vests. But the NRA opposes a ban on the grounds that any government controls on guns or ammunition are bad.

Yet Reagan's support of the NRA is not quiet. He traveled to Phoenix last spring to address its convention, lambasting gun controls in language right out of the NRA handbook. He promised to work to soften the modest existing federal gun controls.

Another example: the Reagan tax program. The president has always sold it as benefiting all Americans, but the benefits have hardly been equal for all.

In the year before Reagan took office, corporate taxes amounted to 12.5 percent of federal tax revenues. By 1983, the percentage had dropped to 6.2 percent, giving American companies one of the biggest tax cuts in history. In constant dollars, the $37 billion corporations paid the federal government in taxes in 1983 was the lowest amount since the fiscal year when Pearl Harbor was bombed. Instead of calling attention to that fact, the Reagan White House emphasizede value of the tax cuts to the average American.

However, poor and working-class Americans got barely any benefit from the president's three-year tax plan. According to a study on how the Reagan tax policies are affecting the American taxpayer by Dean C. Tipps and Robert S. McIntyre, director of the Center on Budget Policy, this year the total federal tax burden (including Social Security taxes) on the 34.2 percent of all Americans who earn less than $10,000 will have by 24 percent under the Reagan program. And the middle-class -- those earning between $20,000 and $50,000, about 30 percent of the population -- will get tax cuts of at most 4 percent.

And how will the rich do? There will be a 14 percent tax cut for the .7 percent of taxpayers who earn between $100,000 and $200,000 or a 17 percent tax cut for the .2 percent of taxpayers earning over $200,000, according to the congressional Joint Committee on Taxation.

Reagan also promised in his 1980 campaign that he would "get the government off the people's back." In fact, most deregulation has been targeted at the rules governing how American business operates. In many cases, regulatory agencies under Reagan have adopted aggressively friendly attitudes toward the industries they regulate. Rita Lavelle and her colleagues at the Environmental Protection Agency were perhaps the best- publicized example of this, but there have been many more.

"Our members do see a perceptible change, a lessening of nit-picking," said Alexander B. Trowbridge, president of the National Association of Manufacturers, in a recent interview.

Reagan similarly has been a boon to the defense industry. In the first year Reagan held office, 1981-1982, the total amount of money for defense contracts leaped 18 percent, to $124.7 billion. In 1983, the amount jumped another 12.7 percent to $140.5 billion. The money for contracts, research and development, production of weapons and military contruction also went up as a percentage of the total military budget. It was 37 percent in 1980 and is 50 percent for the proposed 1985 budget, according to Gordon Adams, director of the Defense Budget Project.

And while Adams estimates the average rate of profit for a defense contractor was 7 to 8 percent under the Carter administration (the numbers are not made public), he now estimates the rate of profit to be about 10 percent. Take the steady climb in gross earnings on production of military aircraft as reported by General Dynamics: 5.8 percent in 1979; up to 7.3 percent in 1980; 9.2 percent in 1981; 11.5 percent in 1982, and a high of 12.5 percent in 1983.

"Mondale is a little bit more direct about it," is the way Lyn Nofziger, the president's long-time political associate, differentiates between Reagan's special-interest politics and Mondale's brand of the same gooey oil of American political life, the stuff that makes an elected official accountable to the voters who eleced him.

"I don't think the president has gone out and promised something to everybody he could find," said Nofziger, who was asked the question after telling a crowd of realtors in Nashua, N.H., that the president had helped their business by lowering interest rates. "I think Mondale has made promises in return for specific help with his campaign. I don't think we have gone out and made promises for something."

Sen. Robert Dole (R-Kan.), traveling through New Hampshire last month as a campaign surrogate for Reagan, said that it is hard to point fingers at who benefits from Reagan's special-interest politics: "Mondale has specific allies. To say the far right or veterans are our special interest group is difficult to demonstrate. You can't say that about the special interest groups lined up behind Mondale. The NEA (National Education Association), the AFL-CIO are specific groups and that is seen on the public side. I'm not critical of it, but it's a two-edged sword and Mondale and the public understand it."

Sometimes Reagan's sleight-of-hand performance at hiding his care of special interest groups can be seen on the campaign trail. In Macon, Ga., earlier this month, Vice President George Bush announced to a political rally that "the Reagan administration had a part to play in the economic growth of your city," with a $1.55 million Urban Development Action Grant. A reporter asked Bush if that wasn't the "same pork-barrel politics that you and the president were criticizing President Carter for in 1980."

"I think there are different degrees of things," said Bush. "When you have $12 million in investments going with it, stimulating private investment, that is in keeping with our philosophy...."

In other words, special assistance to a particular group or city is high principle if it's "in keeping with the philosphy," not pandering for political benefit.

This kind of thinking may explain Reagan's efforts on behalf of tuition tax credits for the parents of children in private schools. According to Reagan, these tax credits would not hurt the public schools but make them "competitive" while increasing options for parents, particularly the poor. At the same time, Reagan maligns the public schools, while cutting federal support for them.

Who would really benefit most from tuition tax credits? Wealthier Americans, obviously. Why do public schools administrators almost universally oppose the credits? Because they understand how they would encourage middle-class flight from public schools, and they know what happens to public schools with few middle-class students. Therefore the NEA backs Mondale.

In Reagan's rhetoric, however, only the other guy is in favor of special interests. Anything favored by him and his most ardent supporters is a policy or program that is good for everybody -- in the national interest.

"Those of you before me have achieved in life, not as a result of any special treatment or artificial quotas or political favoritism, but as talented individuals on your own," Reagan told an Hispanic group last year during his sudden courtship of that group of Americans, seen by some as an effort to counter the hostility of blacks to the Reagan administration.

Before another Hispanic group, he explicitly absolved them of qualifying as a special interest. "Well, yes, government must recongnize the legitimate rights and concerns of individual Americans and the social, ethnic or racial groups they belong to," he said, "but Hispanics know the future of freedom depends not on 'What's in it for me,' but on the ethic of what's good for the country.... The calculus of self-seeking is not for you. Duty, honor and country are."

And so it was that Hispanics, more good Americans than a special interest group, were honored by the president with a special ceremony for Hispanic medal of honor winners in the Rose Garden and an increase in the number of Hispanic political appointments in the administration. And when he spoke in El Paso last year to heavily Hispanic crowd, Reagan announced that he was starting an "interagency group" to study the effect of the Mexican peso devaluation on South Texas.

"Reagan used the theme that Hispanics had been ignored and then discovered by him," said Arnoldo Torres, executive director of the League of United Latin American Citizens. "If that isn't a special interest ploy I don't know what it is. I have no problem with being annointed a special interest, but unfortunately his efforts have not gone far enough to create a substantial change in Hispanic life in the United States."

In New Orleans last summer, Reagan told the Veterans of Foreign Wars: "I haven't forgotten your support in 1980." Then Reagan announced: "As a demonstration of our common goals ... I am going to sit down here in front of this audience and sign the Emergency Veterans Job Training Act."

And Reagan has not forgotten the Teamsters -- the one union close to the president -- although since 1981 his Justice Department has been probing charges that its president, Jackie Presser, was involved in an embezzlement scheme. The Reagan White House has long withheld a trucking deregulation bill because of Teamster objections, according to White House aides.

Reagan cannot hide these actions, but he manages to deflect attention from their significance. The audience seems distracted by his talk about selfish interest groups while his hands are stroking his own favorite interests.

Not that Reagan hasn't had some difficulty assuaging the interests that support him. After three years in office, for example, many of the New Right groups that are most concerned by "social issues" like abortion and prayer felt mistreated. They complained that the White House has been overrun by Ivy League moderates who won't let "Reagan be Reagan" and they complain that conservatives don't have access to the Oval Office.

So at the start of this year Reagan began a drive to "reenergize" his New Right base. He began to push school prayer in the Congress; he spoke about the pain that fetuses feel during abortion; he called for a restoration of "traditional values."

But even as Reagan plays the special interests group game, he leads the chorus denouncing the sport as primitive and damaging to the nation. "We have just emerged from an era of special intersts, a sad time when coalitions were built with an eye toward the next election, not what's good for the country," Reagan told one of those Hispanic audiences cited earlier.

Then, apparently referring to Mondale, Reagan added: "Some would have us forget what that kind of politics did to us.... Today, many who still practice the politics of that past would take you back to the days of lost opportunties, special interest politics, tax and spend and spend.... It was special-interest politics that tripled federal spending in the 1970s and special-interest politics that doubled federal taxes in just five years between 1976 and 1981."