A diplomat here once described the way Muammar Qaddafi runs his country as "organized disorganization."

Without him, there could well be complete chaos. And from that, some diplomats here believe, a Soviet client state could emerge.

As Washington has exerted fierce effortsthis year to punish and undermine the man it sees as a terrorist godfather, several western diplomats here have become concerned that little thought is given to what might replace Qaddafi if he is ousted or killed.

Leaders of exile groups in Britain, Egypt and elsewhere have no discernible credibility or following here.

The only group thought capable of actually seizing power is the Army, and the U.S. covert action plan against Libya originally approved last year was conceived partly in the hope that destabilization might give Qaddafi's presumed opponents in his armed forces a chance to make their move.

But as one diplomat whose nation has military ties to Libya pointed out this afternoon, "It could be a situation tailor-made for the Russians to take advantage."

By far the largest group of foreign military advisers here is from the Soviet Union and its allies. Some estimate up to 6,000 Soviet Bloc advisers for the 73,000 Libyan military -- roughly one for every 12 soldiers.

Until now, Qaddafi has used the Soviets to acquire arms and training, but he has refused to allow them bases here at the center of the Mediterranean. His first meeting after the Tuesday morning bombing, however, was with the Soviet ambassador, and he has called on the socialist countries for more support.

For all that, as many countries have learned, there is usually a price for such Soviet help, and Qaddafi, tied to his radical vision of Islam and fiercely independent, has been unwilling to pay it.

Others might.

"If anyone has a Babrak Karmal hidden away, it's probably the Soviets," one western observer said tonight, alluding to Afghanistan, where the Soviets installed a new leader after it found the regime, although sympathetic to Moscow, too independent.

But a seizure of power by any group here in a cleanly executed coup appears unlikely. And if Qaddafi were simply to be killed, the ensuing confusion could be disastrous in many other ways.

"Do you know what this place would be like?" one seasoned Asian diplomat asked today. "Total chaos. Who is going to replace him?"

A large part of Qaddafi's ability to maintain power for more than 16 years has been his skill at keeping potential rivals afraid of him, or so afraid of each other that they never have the power to make a move.

No institution has felt this policy more than the Army. For the last several years Qaddafi has worked to keep Libya's military off balance. Often, he has vowed to abolish it.

"They would like to have power and when we dismantle it and give the people power they can no longer do so," Qaddafi told reporters in January.

In effect he has created a rival force, the Revolutionary Committees, to represent this "people power." Armed and pervasive in all walks of life, including the armed forces, these committees have often been at odds with the Army's commanders.

When plots against Qaddafi from within the military were discovered in the past three years he is believed to have executed scores of officers. At the same time his reliance on the Revolutionary Committees increased and they became, in the eyes of some diplomats here, a virtual state within a state, capable of imposing their own justice and giving their own orders.

But the growing confrontation with the United States once again brought home to Libya the need to strengthen its regular forces. Some of the Revolutionary Committees' prerogatives have been taken away. They no longer have their own jail in the capital. There are some reports that they no longer dominate Qaddafi's elite guards.

The balance at the moment is unclear, however. Most of the armed men on the streets of Tripoli since the bombing have been dressed in civilian clothes.

Without Qaddafi to dictate an equilibrium between the committees and the regular Army it is conceivable that something like a civil war could break out.

Already there are suspicions among some diplomats that not all the shooting yesterday at Qaddafi's Azizzia barracks and around the old television station was directed at surveillance planes flying overhead. By some accounts, there were brief exchanges of shots across the street, possibly from rival factions.

Yet beyond speculation built mainly on gleanings from the official press, little is really known about the relationship between the men who head the armed forces and the Revolutionary Committees.

Brig. Abu Bakr Younis Jabir, the armed forces commander, and Abdul Salaam Jalloud, who directs the Revolutionary Committees, have both been close to Qaddafi since before he took power in 1969. Both have participated in the shaping of Libya's revolution and it is conceivable that both might find a way to continue it even if he were gone.

One Arab source said that he visited both men today and that they were working closely together.

The names of other potential successors do not immediately leap to mind in this country where there is only one leader. Libya, like many Arab nations, also has strong tribal loyalties and resentments.

If Qaddafi were overthrown, these might come into play as well and further embroil the country in violence. The result could look like the murderous fighting in South Yemen in January, where 10,000 people are said to have died.

Unlike South Yemen, however, this is not yet a client state and the Soviets would have little chance of restoring order quickly if it collapsed. Neither Moscow, Washington nor any European power would find itself in a position to impose peace without sending troops.

From one viewpoint, that of stopping Libyan-inspired terrorism, chaos here might seem a good thing. But the record of the other Arab country reduced by foreign attacks to complete anarchy -- Lebanon -- does not hold out much hope for the future in that regard.

Qaddafi, for all his eccentricity, has led his country within a definable set of values. Though alien to the West, those values that have led to his support of groups using terrorist tactics are shared by many people in the Arab world.

Their centerpiece is the Arab sense of injustice at the treatment of the Palestinian people and the Arab need to vindicate the Palestinians by attacking Israel.

Killing Qaddafi would do little to diminish that ardor, and it might well make of Libya not only a training ground, but a breeding ground for the kind of terrorists that the world discovered most recently in southern Lebanon.