Pressure builds on both sides for arms control. US expected to offer Soviets a timetable on SDI research

Ronald Reagan and Mikhail Gorbachev are coming down to the wire on the crucial issue of arms control. As Secretary of State George Shultz heads for talks in Moscow next week, there is a realization in Washington that the superpower leaders do not have much time left to achieve progress on nuclear arms reduction. In political terms, both leaders could use an agreement - President Reagan to get beyond the Iran-contra scandal and ensure his place in history and General Secretary Gorbachev to ease the nuclear face-off in Europe and give his country breathing space to rebuild its economy.

In terms of nuclear stability, achievement of an agreement on eliminating intermediate-range forces (INF) in Europe - the most promising area for early progress - could lend momentum to the more crucial negotiations on strategic nuclear arms. Diplomatic and arms experts believe it is still possible during Reagan's tenure to work out at least the broad principles for an accord to reduce such weapons.

Administration officials say that strategic arms will be a high priority for Mr. Shultz, who will be looking for the Soviets to address the issue of sublimits, i.e., reductions in various categories of weapons. ``Our big emphasis will be on START [the strategic arms control talks],'' Kenneth Adelman, director of the Arms Control and Development Agency, said yesterday. ``We have more to gain from START than from INF.''

The major stumbling block to an accord on strategic weapons remains Soviet concern about the President's Strategic Defense Initiative or antimissile space program. Washington seeks to delink START from the SDI issue. Mr. Adelman hinted that Secretary Shultz is carrying some proposals on SDI that might interest the Soviets. He also said the US would offer a timetable on SDI experiments in exchange for information on the Soviet antimissile research program.

In the opinion of some arms analysts, the Soviets may show flexibility on the SDI issue, once they conclude that congressional constraints on SDI as well as chronic infighting in the Reagan administration will effectively take care of their concerns.

Shultz's arms agenda will also include nuclear testing. The Soviets have dropped their insistence on negotiating a ban on all underground tests and to focus first on setting new limits on nuclear tests.

The secretary of state will be seeking tighter verification of nuclear tests to make possible the Senate's ratification of the 1974 and '76 treaties limiting tests to 150 kilotons. This would set the stage for further talks to limit the number and explosive force of tests.

On the INF negotiations, two main problems need to be resolved:

Verification. The US has proposed tough measures to monitor verification of an agreement, which would eliminate all medium-range missiles in Europe, leaving 100 warheads on each side to be deployed in Soviet Asia and on US soil. These measures include on-site inspections to monitor the present inventory, dismantling of the missiles, and the residual force.

The Soviets have agreed in principle to on-site inspections, but these raise troublesome questions for both sides.

Pentagon officials are not keen on letting Soviet inspectors into US military installations and production facilities. The verification issue is perhaps the most critical because of its implications for future accords.

The shorter-range systems. An INF agreement would deal with the medium-range Soviet SS-20 missiles and the US Pershing 2s and cruise missiles installed in Europe as a counter to them. The shorter-range systems (weapons having a range of 300 to 600 miles, in which the Soviets have a preponderant advantage) were not previously a concern, but are now the subject of intense debate in Washington and European capitals.

The US insists on the right to match Soviet levels and would like concurrent negotiations on the shorter-range weapons. The Soviets indicated recently they would agree to a freeze in the course of current negotiations and then discuss limitations, reductions, and even the elimination of short-range systems in subsequent negotiations.

American officials are sensitive to the propaganda advantage a sweeping zero-zero proposal would give Moscow but, like many Europeans, are uneasy about such an option.

Complicating matters is the so-called ``conversion'' issue. The Pentagon would like to convert the Pershing 2s into shorter-range Pershing 1Bs. The Soviets are concerned about such a development because in time of crisis the US could convert back to the longer-range missile capable of hitting Soviet territory. If Moscow does formally propose ``zero'' shorter-range missiles, this would in theory eliminate the conversion issue.

Amid the confusing array of possibilities, there are hints that the Soviets may also be willing to dismantle all medium-range missiles, something the US does favor.

Until now the Soviets have insisted on keeping 100 warheads targeted on Asia.

Arms experts note that such a small deployment by each side is costly and irrelevant, given the thousands of warheads that each side possesses. Reducing to ``zero,'' moreover, would greatly ease verification problems.

While most experts in the arms control community favor the proposed INF agreement, some influential voices in Washington do not. Former Secretary of State Henry Kissinger wrote recently that the removal of the Pershing 2s and cruise missiles from Europe would decouple Europe from the US politically and eliminate the American ability to retaliate from Europe against a Soviet attack. Critics also question the wisdom of removing the US medium-range missiles when such a strenuous effort was required to overcome European opposition to deploying them in the first place.

But Reagan officials point out that it was the US that first proposed eliminating the medium-range missiles, that Mr. Gorbachev has accepted the longstanding proposal, and that it would be politically embarrassing and damaging for the administration to back off. Paul Nitze, a senior arms adviser to the President, and other high US officials argue the US will have plenty of nuclear weapons left for the defense of Europe, including the nuclear-capable aircraft in Europe.