Secretary of State Cyrus R. Vance arrived in Moscow tonight determined to switch the pattern of U.S.-Soviet arms negotiatios to "deep cuts" in the two nations' arsenals of intercontinental weapons.
Strong Soviet opposition to this initiative by President Carter casts a cloud of uncertainty over this first major East-West venture of the Carter administration. Even before the approach is unveiled in detail, the Soviet Union is suspicious of it because it is a marked departure in the ongoing Strategic Arms Limitation Talks (SALT).
Vance received what diplomats call "a correct" but no enthusiastic reception as he landed at Vnukovo airport. He was greeted by traditionally deadpan Soviet Foreign Minister Andrei A. Gromyko, lesser-ranking diplomats and reporters.
"The purpose of my visit," said Vance, "is to enter into substantive discussions out of which I hope will come a framework for the negotiations of a SALT II agreement." He added, "I hope that my visit makes clear that detente remains in our mutual interest and that we shall take steps to further detente."
Soviet leader Leonid Brezhnev on Monday firmly cautioned the United States that pressure on himna rights in the Soviet Union is unacceptable interfernce in internal Soviet affairs. Nevertheless, the Kremlin is more concern at present about the U.S. bargaining position on SALT, according to Soviet diplomats.
Soviet diplomats in private have said that they are prepared to move beyond the human-rights dispute to complete the nuclear arms control objectives set out by the United States and the Soviet Union at Vladivostok in 1974. What the Kremlin will not do, these sources said in advance of the talks, which officially begin Monday, is to start bargaining on a fundamentally different premise of major arms reductions in this stage of the arms reduction talks.
Abroad his Air Force jet en route to Moscow, Vance told reporters that the U.S. priority, as President Carter first outlined on Thursday, is to press for "deep cuts" in Vladivostok force levels.
To reinforce that determination, the normally mild-mannered Vance said that the United States will be willing to discuss variations on "minor aspects" of its approach, "but not the essentials."
"The essentials of the comprehensive package," Vance said, "we think are fundamental and not subject (to abandonment)."
As President Carter explained at his news conference Thursday, Vance will present "two alternative packages to the Soviets, with hopes that we will be able to reach agreement as to one of the two (nuclear) packages."
The narrowest U.S. option is to conclude the 1974 plan which would limit American and Soviet forces to those projected at Vladivostok with 2,400 intercontinental nuclear missile launchers and bombers on each side. This proposal is exremely unattractive to the Soviet Union in its present form. It excludes any controls on the two most controversial weapons systems, which have confounded negitations since the Vladivostok accord: long-range Cruise missles, which the United States is developing, and the Unit Soviet bomber known as Backfire, which the Soviets insists is not an intercontinental weapon.
To gain any limitation on the American-iniated long-range Cruise missiles, which can be launched from land, sea or air, the Soviets would have to turn to the American arms-reduction formula. They insist that it is premature to do so now, and that the priority must be on concluding the Vladivostok approach - with restraints on Cruise missiles.
Vance, however, said the arms-reduction alternative, which would fundamentally revise the Vladivostok plan by "substantial reductions" in force levels, will be "the central piece of our discussion" in Moscow, so far as the United States is concerned.
He told reporters: "The objective of SALT is to reduce the arms race and to make real progress in cutting back on the number of nuclear weapons on both sides . . . the sooner we can get on to making real progress, the better off both sides are.
Vance added: "By going to deep cuts you're going to end up with greater stability and greater stability lessens the likelihood of nuclear war. It's as simple as that."
Until the still-secret U.S. reduction formula is presented to the Soviets, U.S. officials refuse to say how deep a cut they are proposing inthe Vladivostok nuclear-arms level.
Asked what Soviet reaction he expects to this major turnabout in the U.S. negotiation posture, Vane said dryly, "I would gather from what I have read in the newspaper that there will be hard bargaining on both sides, but I hope that the atmosphere would be businesslike and cordial. Certainly from our side that will be the case."
The U.S. delegation currently is scheduled for only three days of working sessions in Moscow, with talks running-from Monday through Wednesday, and departure Thursday. Vance said it is possible the visit will be extended "if we are making progress." In that case, he said, he would be prepared to "stay on and pursue our discussions . . . however long it should take."
Vance added, however, that he thought an extension is "unlikely." In any event, he said, "I would expect that teh would give us formal reply during the period we are in Moscow."
What the United States wants, Vance said, is to "reach agreement on a framework which would guide negotiations which will have to follow in Geneva for a SALT II agreement."
Asked if he is "very optimistic," in view of the basic Soviet opposition to changing the Vladivostok guidelines, Vance replied: "I have never said I am very optimistic. What the President has said was that he ahd high hopes we would be able to reach agreement with the Soviets. I don't want to characterize ourselves as very optimistic . . . We would be hopeful."
Vance said that he also expects in Moscow a discussion about Soviet frustration on expanded trade with the United States, what he described as "the need to exclude outside forces" from teh African continent, and the Middle East. While the United States will urge curtailment of the arms race in the Middle East, Vance noted, it has been the Soviet position that curbs on arms sales should await an Arab-Israeli peace settlement.
Vance stopped off in Brussels on the way to Moscow to inform the North Atlantic Council of Ministers of U.S. plans for the Moscow talks.
As Vance landed in Moscow, the weather was a mild 36 degrees with only traces of snow on the ground. Missing from his reception was the sense of excitement that accompanied the arrival of his more dramatic predecessor, Henry A. Kissinger. Tonight there was instead a sense of uncertainty on both sides, American diplomats concede, about the unknown outcome of Vance's meeting with Brezhnev and other soviet leaders.