The Kremlin has been thrown into utter confusion by President Carter's latest decisions. For years Moscow has been threatening, begging and cajoling the United States to give up the B-1 bomber project, but without any real hope of success. Now that Carter has done just that, the Kremlin refuses to believe he means it.

A decision to give up the B-1, Moscow has often argued in the past, would provide a welcome sign of moderation in Washington's policies and of restraint in its arms drive. Now, however, Pravda says that the decision can hardly be taken as a sign of "moderation or restraint."

Why not? Because Carter simply had "no other way out," his hands having been tied by his "election promise" to give up the B-1. The Kremlin's newfound faith in the inviolability of U.S. election promises is a sure sign of its discomfort. Pravda has often explained to its readers that election promises are meant to gain votes, not to prejudge future policies, and has illustrated its argument with convincing examples. Only a few days before Carter's decision was announced. Pravda's foreign editor. Eugene Grigoryev, wrote of Carter's coming decision in favor of the B-1 as virtually a foregone conclusion.

Krasnaya Zvevda, the army paper, recalled Carter's election promise only to point out that he was now changing his mind and that in doing so he was making concessions "to the military-industrial complex, the Pentagon and the hawks." On Moscow television, Pravda's chief diplomatic correspondent, Yuri Zhukov, made a welcome reappearance, after an illness of several months, to describe "the indescribable joy of U.S. arms-manufacturing monopolies, which expect enormous profits from the sale of these fantastically expensive types of arms."

The authors of these remarks are the big guns of the Soviet propaganda machine, and they stand sufficiently close to the center of decision making to reflect in their own writing something of the attitudes of the policymakers. In Washington, too, most analysts were caught unawares by Carter's decision, but in Moscow the underlying assumption for several years has been that the United States was going ahead with the B-1, which was regarded as one of the most serious threats to the security of the Soviet Union. This predetermind a whole range of Soviet policy decisions in the fields of arms control and arms production, and committed large segments of the bureaucracy to these decisions and to the analysis of likely U.S. policy on which the Soviet decisions were based.

Many of the Moscow policymakers, not to mention the journalists who reflect their views, cannot afford to take Carter's decision on the B-1 at its face value. They have to insist, as Pravda does, that his decision is "not final," that it is "equivocal," because their own credibility depends, paradoxically, on proving somehow that Carter cannot possibly mean what he says.

As distinct from Carter's decision on the B-1, his decision to go ahead with the air-launched version of the cruise missile was fully expected in Moscow. Indeed, it was accepted by both sides in the earlier negotiations that U.S. bombers would be equipped in the future with cruise missles, and there was even something close to agreement on their range and numbers. It was the land-based and sea-launched cruise missiles that presented the major difficulty in Moscow.

At that time, indeed, Moscow seemed ready to accept the almost inevitable prospect that a new fleet of B-1s, equipped with the most sophisticated refinements that modern technology could provide, would take to the air before long, with cruise missiles as its main armament. Now, however, the Kremlin is protesting bitterly at the prospect that the far less advanced B-52 bombers are to be equipped with cruise missiles.

Why? One reason, no doubt, is that the Carter administration has now withdrawn Kissinger's offer, which Secretary of State Cyrus Vance confirmed in his own negotiations with Moscow, on how the cruise-carrying bombers should be counted in the total number of weapons allowed by the strategic arms limitation agreement. Under the agreement, the United States is allowed 2,400 missile launchers, of which only 1,320 may contain missiles with multi independently targeted re-entry vehicles (MIRVs).

Washington originally proposed that each cruise-carrying bomber should be counted as a MIRVed missile under the 1,320 ceiling allowed by SALT, but now it wants each such bomber to count as the equivalent of an un-MIRVed missile under the 2,400 total. This would allow the United States to regain its present total of MIRVed missiles without giving up some of them in exchange for the cruise-carrying bombers.

Pravda sees Carter's decision to go ahead with the air-launched cruise missiles as "alarming evidence of the U.S. intention to step up military preparations and to start a new spiral in the arms race. But Moscow chooses its words carefully, and it does not see the Washington moves as closing off the possibility of accommodating the air-launched cruise missiles in a new arms-control agreement. The cruise issue, Pravda explains, is a vital part of SALT and it is therefore "logical to ask" whether it is the U.S. intention to "aggravate deliberately the difficulties" in reaching a new agreement.

Thus, in spite of all the sound and fury that seems to emanate from Moscow, the Kremlin is still "asking" whether the U.S. is "deliberately" making difficulties or whether there is some other explanation of its new proposal. It is not a rhetorical question. There are evidently those in Moscow who would welcome a more detailed and elaborate presentation of how the new decisions fit into the arms-control negotiations. If Carter had put his original announcement in some such context, he would have taken at least some of the wind out of the sails of those in Moscow who automatically react to every American move as unacceptable.

In devising the U.S. tactics for the Vance mission to Moscow earlier this year, National Security Adviser Zbigniew Brzezinski sought to have the arms proposal presented directly to the Politburo in the first place to prevent it from being filtered through the destructive criticism of the experts in the Soviet defense ministry, who have a monopoly on this kind of analysis in Moscow.

It would have helped if Carter's latest ideas had been similarly protected and explained.