It was seen in Washington as a critical battle for Ronald Reagan's mind. And when the president announced Monday that he would not undercut the restraints of the unratified SALT II treaty, he was praised by his critics for an act of statesmanship that could save the arms control process.

Why, then, did the Soviets so quickly and firmly dismiss Reagan's move? Why did they see it as merely a sophisticated public relations gimmick? Why do they continue to believe that the president was not going "the extra mile" for arms control but rather for the "destruction" of all arms agreements between the two superpowers?

Answers to these questions can be found in Soviet public and private statements during the past few months. Underlying them is the continued deterioration in bilateral relations, domestic circumstances, anger, pride and -- above all -- suspicion that have locked the leaders of both countries onto a course whereby neither seems willing to take a major step toward the deescalation of the conflict.

Looking from Moscow, one can clearly define three areas through which Soviet officials explain their current position.

First is the technical aspect put forward by a number of senior figures, including the defense minister, Marshal Sergei Sokolov, and Marshal Sergei Akhromeyev, the chief of staff.

The Soviets see the United States moving inexorably toward abrogation of the 1972 Antiballistic Missile Treaty, which they regard as the foundation for SALT I, SALT II and all other existing or contemplated arms agreements.

Akhromeyev put this view succinctly when he said that restraints or reductions on offensive nuclear means (such as those provided under SALT II) are "unthinkable" without the ABM treaty. That treaty, in Moscow's view, is now gravely threatened by Reagan's Strategic Defense Initiative, also known as "Star Wars."

While the president was announcing his SALT II decision, his senior advisers were publicly stating that some elements of SDI could become operational during Reagan's presidency.

The Soviets are convinced that the United States is busily testing components of the new space-based missile defense system. As Col. Gen. Nikolai Chervov put it recently, referring to Reagan advisers' statements, "they are not going to make this out of papier-mache."

In the simplest terms, the Soviets, according to their statements, believe the president is contemplating setting up a defensive shield around the United States, while the ABM treaty allows each side to erect only one such shield around a specified area (either the nation's capital or a military installation).

SDI, apart from being a violation of the treaty, would introduce new strategic problems that would make SALT II obsolete, they say.

The Russians have repeatedly asserted that they would not tolerate a change in the strategic parity and that their counterresponse would nullify any possible U.S. advantages. Moreover, they have made it clear that their response would focus on a qualitative and numerical buildup of their offensive strategic means.

Hence, that the president should be willing to continue compliance with the unratified SALT II, which he had described as "fatally flawed," is seen here as sinister or, as one senior analyst put it, even "comical."

The second Soviet concern is political. Reagan's SALT decision was qualified in a way that served to reinforce Moscow's view that his policy toward the Soviet Union is one of "pure intimidation" and continuous search for leverage over domestic Soviet affairs.

The Soviet government statement on this issue had made it clear that the Russians do not intend to play Reagan's perceived game.

Privately, officials here see Reagan's decision as just another "coercive tool" to be used to keep Moscow off balance and "in continuous suspense."

The move to remain in compliance with SALT II is seen as having a double purpose. On the one hand, officials say, it was designed to encourage those elements in the Soviet elite that still believe in the possibility of an arms deal with Reagan.

In pursuing this objective the Americans are operating on the assumption "that we are more interested in the fate of SALT II than they," one said.

On the other hand, according to a senior official, "they decided not to undercut the treaty at this time in order not to frighten us too much." The decision came at a time when the Soviets are drafting their economic plans for the next five-year period and are presumed to be concerned wilh the prospect of an economically ruinous arms race.

The Russians are particularly angry at another "coercive tool" the president reintroduced in his decision Monday -- namely his allegations about Soviet noncompliance with SALT II provisions and in particular his stated intention to change or modify his decision by using this tool at a time of his choice.

This suggested to Moscow that his decision was tactical. Officials charged here that the wording of the president's announcement was an example of double talk. While denouncing Moscow for continuing an "unparalleled and unwarranted military buildup," he did not make any specific demands for a change in Soviet actions for continued observance of SALT II.

The third, most important Soviet concern is strategic. The Soviets take SALT II as part of Reagan's overall policy toward the Soviet Union, linking "Star Wars" firmly to their assessments of U.S. intentions.

The Soviet leadership has been advised by its top scientists that a defensive shield planned by Washington would not be effective in case of an all-out surprise attack on the United States.

However, if the United States were to launch a first-strike attack on the Soviet Union, the space-based antimissile systems could prove effective to a considerable degree in deflecting a Soviet retaliatory strike.

This has led Soviet strategists to conclude that SDI is a strictly offensive system since its effectiveness depended on a preemptive U.S. attack.

Consequently, the Russians see this as not only a highly destabilizing factor likely to increase U.S. temptations to attack the Soviet Union but also a program reflecting such intentions at a point where the United States gains strategic superiority over the Soviet Union.

This argument is reinforced by the fact that the United States plans a steady growth of its offensive nuclear means through the rest of this century.

Another broader strategic concern rests on a perception here that the ultimate objective of Reagan's rearmament program, military budgets and policy toward arms control is to suffocate the Soviet Union economically. As Georgi Arbatov, a Kremlin adviser on American affairs, put it recently, all this is designed "to delay socioeconomic development" of this country.

The Soviets see Reagan and his aides as being mesmerized by what they believe to be a great technological advantage enjoyed by the United States. According to this view, the American leadership believes that the sharp escalation of costs in a new arms race will exert intolerable pressures on the Soviet economy and that an economic collapse would lead to a political collapse.

In this context, SALT II and other treaties are seen as being used by Washington as "coercive options" along with western efforts to stimulate internal dissent, spread news about ethnic and religious discontent as part of what Chervov called an "all-out psychological war" against the Soviet Union.

Officials here give the impression that the prospects for the Geneva talks are gloomy and that little headway could be made without an improvement in U.S.-Soviet relations.

Finally, the Russians are convinced that Reagan's statement Monday was not directed at Moscow but at his various domestic constituencies, at Congress and at Western Europe. As such, one Soviet official said, the statement "is a work of a public-relations genius."

The upshot is a delay in making a decision that makes Reagan look conciliatory and statesmanlike. But the United States in the meantime will proceed with a mobile, single-warhead "Midgetman" missile as supplement to the large, 10-warhead MX and continue developing esoteric technologies that threaten what the Soviets see as the most important of all arms agreements, the 1972 ABM treaty.

It is apparent that there is a new mood in Moscow.

After the turmoil of three successive leadership transitions, the ruling elite has regained confidence and the impulse to reshape society. It is unclear how radical these changes will be.

Given the almost complete preoccupation of the new Soviet leader, Mikhail Gorbachev, with domestic matters, one has the impression that the Russians would genuinely try to preserve the arms control process.

Given Reagan's policy, however, there will be temptations here to use the external challenge for domestic purposes in Gorbachev's efforts to mobilize society behind his modernization program.