US watches for Soviet flexibility on Afghanistan withdrawal. After proposing its own plan, US hopes for positive Soviet response

This could be a crucial week in the search for peace in Afghanistan. As the UN-sponsored talks on Afghanistan resumed in Geneva yesterday, administration officials said the next few days should tell whether Soviet leader Mikhail Gorbachev is prepared to be more flexible on a negotiated settlement of the war. He seemed to hint at this in the recent summit meeting with President Reagan.

If progress can be made on the Afghanistan question, United States officials say, this would significantly improve Soviet-American relations across the board and enhance the prospects for an arms control agreement.

``Afghanistan is symbolically so important,'' says a ranking State Department official who was involved in the summit talks. ``That's what led to the breakdown of the SALT II agreement. So if that could be solved, it would set us on a healthier road.''

In an effort to smoke out the Soviet position, the US last week publicly announced its willingness to serve as a guarantor of a peace settlement that included a Soviet troop withdrawal and an end of outside aid to the rebels fighting the Soviets. Diplomatic experts welcome the move even while cautioning that it is only one step along what still seems a long and difficult road to a settlement.

``It was an important step which was essential to bringing things to a head,'' says Selig S. Harrison, a senior associate at the Carnegie Endowment for International Peace. ``The US has gone as far as it can at this stage on the issue of guarantees. Now it will test whether the Russians are serious about withdrawal and respond with greater flexibility.''

The heart of the stalemate is the timetable for Soviet withdrawal. Under a four-part negotiated settlement, Moscow has insisted on talking about a pullout from Afghanistan only after all other elements of the accord are in place, including all US assistance to the mujahideen fighting the Soviets.

Washington's position is that the process should be simultaneous, i.e., a Soviet withdrawal simultaneous with a halt of US assistance. The controversial ``fourth instrument'' of the settlement package, which is being negotiated indirectly between Afghanistan and Pakistan, provides no detail about withdrawal but simply links the general issue of withdrawal with the other three aspects of the draft accord: noninterference in Afghanistan's internal affairs, the voluntary return of several million refugees,

and international guarantees.

On the last issue, State Department officials say the US has long given its oral assurances that it was prepared in principle to be a guarantor of an agreement that included Soviet withdrawal, but was waiting for a Soviet timetable. But UN Deputy Undersecretary General Diego Cordovez, who is mediating the so-called ``proximity talks,'' charged that the US was being ``obstructionist'' by not providing a written acceptance, a charge that led Indian Prime Minister Rajiv Gandhi to raise the issue with Presi dent Reagan last October.

According to administration officials, the President expressed surprise at the charge, believing the US was forthcoming on the issue. After the summit and hints from Mr. Gorbachev that Moscow might be more flexible, the administration decided formally to accept the draft text on international guarantees and on Dec. 11 sent a letter to this effect to UN Secretary General Javier Perez de Cuellar. Two days later Deputy Secretary of State John C. Whitehead announced the US position in a public speech.

The talks are now at the critical stage of finding agreement on how Soviet withdrawal and the end of aid to the rebels by the US (via Pakistan) are to be discussed and coordinated.

Diplomatic experts say that, given the basic differences between Washington and Moscow over the nature of the regime in Afghanistan, the talks are a long way from a breakthrough. But the Soviets may make a procedural concession, agreeing to talk about the ``fourth instrument'' before there are direct talks between Afghanistan and Pakistan, as Moscow has been insisting. Pakistan rejects such direct talks until there is a Soviet withdrawal timetable.