House Minority Leader John Rhodes of Arizona is, of course, a partisan politician, but he is respected for the restrained and even-tempered way he usually speaks of the opposition. He seldom criticizes frivolously or extravagantly.

So it is not surprising that his blunt assessment of President Carter's human-rights "crusade" has made legislators in both parties sit up and take notice. The Carter policy, Rhodes says flatly, is "an unmitigated disaster."

Significantly, no one on the Democratic side of the aisle has so far risen to challenge or rebut the Republican leader, for in the president's own party there is a spreading feeling of dismay that Rhodes is probably more right than wrong.

Even a loyalist like Rep. John Brademas (D-Ind.), the majority whip, has openly expressed concern over some of the president's anti-Soviet actions. Brademas wondered whether they might be an effort to appear decisive in order to reverse Carter's decline in the polls.

"That's a very dangerous game to play," said the Democratic leader, who is well versed on foreign policy. "If he's doing this for political purposes, he'll pay a fearful price."

In the U.S. business community, however, the immediate concern is not over the price to the president, but the cost to American enterprise and American workers. Industrial leaders justifiably fear that Carter's trade reprisals against Moscow for its human-rights violations are going to end up hurting the United States more than Russia.

After Anatoly Scharansky, the Russian dissident, was sentenced to prison, Carter canceled the sale of a multimillion-dollar U.S. computer to Russia. He also imposed new controls on sales of U.S. oil technology to the Soviet Union, which could ban deals like Dresser Industries' plan to sell $144 million in oil equipment to Russia.

The head of Dresser, which had already obtained an export license from the Commerce Department, denounces Carter's action as "sheer idiocy." It is no secret that top Commerce officials and others in the State Department substantially share that view.

"Placing oil technology under government control," says James V. Jones, president of Dresser, "will virtually hand American export business to foreign competitors on a silver platter." He explained that the equipment in question can be bought from five other nations, including East Germany, with employment going to foreigners instead of American workers.

Even so, it is questionable whether all this is more self-defeating than the administration's cancellation of mutually beneficial exchange trips to Russia by high-level government delegations in the fields of science, housing and environmental protection. The government, meanwhile, is sending missions to Russia's arch-rival, the People's Republic of China.

Noting this "brazen contradiction," two professors at Harvard, Richard Lewontin and Richard Levins, charge that Carter and his adviser, Zbigniew Brzezinski, have "exploited the human-rights issue in a selective way to line up American liberal opinion for an essentially reactionary campaign, 'playing the China card' in a terrifying game of political poker."

According to two other prominent scholars, Noam Chomsky and Edward Herman, "the Soviets have much to learn from the Latin and Central American clients of the United States about the handling of dissidents." With a perfectly straight face, they say:

"The holding of any trials whatsoever is obviously a great mistake. Consider that Argentina was able to eliminate some 1,000 dissenters in 1975 alone, and Guatemala 14,000 between 1970 and 1975, by the simple use of 'death squads,' with no trials at all, and without suffering the negative front-page coverage the inept Soviets have generated by the trial of two individuals."

The Russians, they think, "would also be well advised to follow the new free-world pattern in its finer nuances and have the death squads always engage in their cleansing operations in 'shootouts with suspected guerrillas,' perhaps 'attempting to flee' their captors in the Moscow suburbs."

Although Rhodes is fairly hard-line himself, he observes that the "Russians didn't start disregarding human rights yesterday." So why all the present excitement in Carter circles? Rhodes puts more reliance on what he calls the "gentle nudge policy."

That, in effect, would be a resumption of the old Kissinger policy of quiet diplomacy, which won freedom for such dissidents as Alexander Solzhenitsyn, inspired relaxation of the Soviet ban on Jewish emigration to Israel and stimulated trade with Russia until congressional cold warriors put a damper on it.

As of today there are still well over 100 nations regularly violating human rights, some more harshly than Russia, with few serious reprisals by the United States. One official says, "the hardest thing to get across to foreign countries is that this is not a domestic political gimmick." How could they be so dense?