The Soviet Union's deep involvement in the Afghanistan coup has a shock value that could prove beneficial to the United States in several areas, a wide spectrum of military leaders said yesterday.

For one thing, they said, the specter of Soviet troops fanning out through Afghanistan underscores the reality that the United States has no launching pad for its own military power in the Persian Gulf area.

The Soviet invasion came less than two months after Iranian militants took over the U.S. Embassy in Tehran and held Americans there at gunpoint. tThe most the United States has been prepared to do in response militarily is mass warships off Iran.

The Iranian crisis spawned a fresh batch of justification papers in the Pentagon for using bases in the Middle East as at least a temporary arrangement. Shortly before Christmas, a team of Pentagon and State Department officials swung through several Mideast countries, seeking permission to use bases.

Washington sources report that Saudi Arabia continued to greet the idea warily, while Kenya, Oman and Somalia were receptive. No formal agreements have been announced, however.

"We have an expression in the Pentagon," said one general in stating that Afghanistan would provide a fresh sense of urgency in the search for bases, "that every time we get in deep kimchi [a spicy Korean cabbage dish], the Russians do us a favor. This is going to help us."

"Afghanistan," said one Navy leader, "has nothing to do with the national security of the United States directly. But it raises the question 'How the hell are you going to get there?'" It thus helps make the case for finding bases in the Persian Gulf area, he reasoned.

An Army officer with Mideast experience said the Soviet intervention in Afghanistan dramatizes that the president has three fundamentall choices when it comes to using military power in the Persian Gulf: "do nothing, find bases, or spend an astronomical amount of money building new planes and ships" that could reach the gulf from the United States.

If military leaders who have studied the problem had their way, the United States would not only obtain permission to use bases in easy reach of the Persian Gulf but would store military equipment there as well. One officer said the ideal would be to duplicate the base of Korat in Thailand someplace in the Middle East.

A second prospective benefit, military leaders agree, is Afghan tribesmen pinning down Soviet troops, Vietnam-style, "It will be interesting," said one general, "to see whether the Soviets occupy the cities and lines of communication and leave it to the Afghan army to go after the guerrillas in the hills, or whether the Soviets go after them."

The latter course, he predicted, would prove difficult and force the Soviets to go after the guerrillas with helicopters -- the same way American troops pursued the enemy in Vietnam.

The image of the modern Soviet military machine trying to crush the native Moslems' uprising would be an exploitable propaganda opportunity for the West, another officer said.

Besides underscoring the need for bases in the Persian Gulf area and pinning down Soviet forces in Afghanistan for an indefinite period, U.S. military leaders said Afghnistan would help cure the Vietnam "never-again" hangover of the American public.

You can't wish the world into a peaceful place," said one officer..

Military views as to why the Soviets moved into Afghanistan varied. One high-ranking official theorized that the Soviets saw the country "slipping away" and were not willing to let that happen. Another saw the intervention as part of a master plan to dominate the oil-rich Persian Gulf.

Still another officer theorized that the Soviets wanted to stabilize the buffer state, predicting this could end up being stabilizing for everybody in that part of the world.

Adm. Elmo R. Zumwalt, retired chief of naval operations, said neither U.S. rights to bases in the Persian Gulf nor President Carter's plans for increasing the defense budget would keep the Soviets from pulling off other Afghanistans in the future.

The United States, Zumwalt said, simply does not have either the conventional or strategic nuclear forces needed to take on the Soviets, and will not have them "for several years, even if Carter moves briskly. And he's not moving briskly, but making frighteningly modest increases in the defense budget."

"It's business as usual while the globe is burning," Zumwalt said. The United States must spend an extra $50 billion a year for the next four years on defense to catch up with the Soviets, he said.