Reagan waits for Soviet offer he can't refuse. Hints that USSR might cut missiles brings mixed White House reaction

Two fundamental questions come to the fore on the eve of President Reagan's minisummit with Soviet Foreign Minister Eduard Shevardnadze. Is the President hanging tough on ``star wars'' because he is irrevocably committed to it, or is he prepared to strike a deal if Moscow comes in with an attractive offer?

Have the Soviets simply been playing a propaganda game by hinting at a proposal? Or are they truly willing to make substantial cuts in their offensive nuclear arsenal in return for some limits on the President's antimissile defense program?

As the President prepares to meet Mr. Shevardnadze tomorrow, administration officials say they expect the Soviet foreign minister to come with a specific proposal in hand. Such a proposal could not be taken up in detail in a two-hour meeting at the White House but would form the basis for discussions at the full-blown summit meeting between the President and Soviet leader Mikhail Gorbachev in November.

In recent days this capital has been teased by numbers floated by Soviet sources. According to a congressional source, the Soviets have told members of Congress and other Americans that the Soviet Union would propose cutting strategic nuclear launchers and warheads by 40 percent. It would also propose that no more than 60 percent of the remaining warheads could be deployed in any one leg of the strategic triad, that is, land-based missiles, sea-based missiles, or bombers, the source said.

In return, the Soviets would expect limits on the President's ``star wars'' program, formally known as the Strategic Defense Initiative. Mr. Reagan has said that SDI is not a bargaining chip and that research must continue.

Arms control advocates in and out of government would regard such a Soviet gambit as worth considering, although many questions remain to be answered. According to a Congressional Research Service, the Soviet Union has roughly 10,000 warheads in its nuclear arsenal, including 6,500 in its land-based missile force. If the purported Soviet proposal were carried out, the Soviets would have to cut 3,000 warheads from its land-based force, the Soviet component which most troubles the US.

But the US would also be concerned about Soviet intentions with respect to its huge SS-18 missiles, which have an enormous throw-weight capacity. If the Soviets modernized their land-based forces by replacing the SS-18, which can carry up to 24 warheads, with their modern SS-24 missile, which has a capacity of 11 warheads, this would help alleviate US concern about Soviet throw-weight, arms experts say.

``Depending on how the SS-18 is handled, the proposal has potential for a signficant restructuring [of Soviet forces] to reduce the alleged problem of imbalance in hard-target attack capability,'' says John Steinbruner of the Brookings Institution.

Despite the President's stand on SDI, administration officials appear eager to counter an impression that possibilities of an agreement are slim because of Reagan's hard-line position. The White House said Wednesday that in his meeting with the Soviet foreign minister Mr. Reagan is ready to discuss ``any serious proposal'' but that bargaining on such a complex matter had to be reserved for talks under way in Geneva.

National-security adviser Robert C. McFarlane has also said that there is ``a very good prospect'' for some kind of arms agreement within the next year.

Arms experts say they believe it would be possible for the President to accept some sort of trade-off on offensive and defensive systems without appearing to have retreated from his vision of building a space-based population defense and abandoning the present strategic doctrine of deterrence, which requires a large nuclear force.

Reagan virtually admitted the link between a defensive system and reductions in offensive weapons when he first launched the SDI concept in March 1983. He said at the time:

``I clearly recognize that defensive systems have limitations and raise certain problems and ambiguities. If paired with offensive systems, they can be viewed as fostering an aggressive policy, and no one wants that.''

Since then administration officials have acknowledged that a missile defense system would not work without sharp reductions in Soviet offensive nuclear forces. A major study by the Office of Technology Assessment released this week also concludes that an effective defense shield would require Soviets to cut offensive weapons.

President Reagan is given credit for genuinely wanting an arms control agreement. But the question asked by many here is whether he adequately understands the extremely complicated subject and has the political will to drive the bureaucracy to work out an agreement. Those in the administration who think an arms control agreement is achievable appear to be waiting for the Soviets to move before pressing the President.

In any case, it is characteristic of Reagan's style to stick by his ideological position until the final hour, and then adjust his position and compromise.

Administration officials suggest that, if a deal is to be struck, one of two pressures (if not both) would have to act on the President. He could conclude, on the basis of technical analyses, that accepting a proposed agreement was the best course for enhancing US security. Or he could determine that the political cost of rejecting a deal -- as shown by the reluctance of Congress to fund SDI, divisions within NATO, and adverse public opinion -- would be too high.