Afghan ruling party digs in. As Soviets leave, prospects for Kabul's ruling party look grim. But a party activist says rumors of the regime's demise are premature.

Soviet officials say they see little hope of their Afghan allies, the People's Democratic Party of Afghanistan, holding onto power much longer. But some PDPA activists think the Soviets are wrong. ``We are the only nationwide political party in the country,'' says Abdullah Naibi. ``We have over 200,000 party members and another 280,000 party youth.'' And, he adds almost apologetically, ``We're all very well armed.''

Mr. Naibi joined the PDPA when it was still an underground organization 16 years ago. He was then 17 years old. He later studied medicine in Strasbourg, France, where he joined the French Communist Party.

When the PDPA seized power in 1978, the new government called him back. He abandoned medicine and became a department chief of the PDPA's Central Committee, and now heads the country's writers' union. He speaks softly and thoughtfully in impeccable French.

He is impatient with Soviet predictions of the regime's imminent demise. If some Soviets are taking an attitude of ``after me the deluge'' about Afghanistan, he says, ``this is probably to try to erase a sense of guilt'' toward the country.

He, in fact, sees ground for cautious optimism. This is largely due to the PDPA's stranglehold on the country's security, police, and military structures. The PDPA as he describes it is less mass-based than military-based.

``Seventy percent of our members are in the armed forces, the Security Ministry, or the Ministry of the Interior,'' he says. The Security Ministry runs the country's secret police. The Interior Ministry is in charge of the regular police. Both have large and well-equipped combat units.

Naibi admits that it is hard to gauge the loyalty of every member of the party and its affiliated organizations. ``But the people who collaborated with us are by definition collaborators'' in the eyes of the guerrillas, he notes. The guerrillas have so far shown little mercy to collaborators.

The PDPA's monopoly over the military and security forces is apparently one of the main reasons the ruling party is willing to discuss the formation of a broad-based coalition government.

A key task facing Yuli Vorontsov, the Soviet deputy foreign minister, who was suddenly named ambassador to Kabul last month, is to form a viable coalition government, something that can keep the country together after Soviet troops complete their departure early next year. There are indications that the Soviets would be willing to give noncommunists a major role in any future government.

(``And if [Afghan leader] Najibullah felt the urge to resign, I doubt that we'd try to stop him,'' one Soviet observer said in Moscow recently.)

But conversations in the last few days with PDPA officials indicate that they are unwilling to abandon the role of senior partner in the government.

Naibi - who stressed throughout our conversation that he was speaking in a personal capacity - feels that the PDPA would be willing to give both the Defense and Interior Ministry portfolios to nonparty members. After all, he noted, the PDPA's strength in both ministries would prevent any nonparty member from establishing real control over them.

According to persistent rumors, the Kabul government has already offered Ahmed Shah Massoud, one of the most charismatic of the guerrilla commanders, the defense portfolio. It turns out that Mr. Massoud and Naibi were near-contemporaries at Kabul's French language lys'ee, and Naibi reacts with enthusiasm at the mention of Massoud.

Massoud's adherence to a coalition government would have a ``spectacular'' political effect, Naibi said. ``It would have the same result as dropping the atom bomb on Hiroshima.'' It would guarantee that the Kabul government would be able to crush the armed resistance, he said. He adds, however, that he does not know whether Massoud has been formally offered a government post.

But Massoud would face the same obstacles as any other non-PDPA defense minister, Naibi predicts.

``He could bring some of his own generals, but he could not control the ministry.'' Besides, Naibi adds, the present leader, Najibullah, should not resign. He should remain both President and armed forces commander in chief.

There is one person with whom the PDPA would not stay in power, says Naibi: the fundamentalist guerrilla leader Gulbuddin Hekmatyar. ``He is a sort of Afghan fascist,'' Naibi says; ``we have, as they say, accounts to settle with him.''

Despite his irritation with Soviet predictions, Naibi agrees with at least part of Moscow's political analysis of Afghanistan's problems. There was no Afghan revolution in 1978, he says. It was simply an armed reaction by a small political party that considered itself threatened with annihilation. He admits to major political mistakes - the urge to produce an exact Afghan copy of the Soviet Union and the desire ``to build a revolution with bulldozers and Kalashnikov rifles.''

But there is a slightly wistful note in his voice when he starts to discuss the PDPA's historical legacy. The government may not be very popular now, he concedes, but it will go down in history as a positive force.

``We have destroyed the Middle Ages in Afghanistan. The old structure has gone, but we can't predict what the new structure will look like. But we have brought the country into the 20th century by means of 10 years of war.''