Libya's Col. Muammar Qaddafi, vilified by Western nation as a promoter of terrorism and frequently named as a target for overthrow, seems to have thrived nonetheless in his 12-year-old dictatorship by skillfully manipulating the interests -- from oil to weapons -- of his most likely enemies.

Qaddafi's threat to Western interests -- manifested in his flamboyant sponsorship of guerrilla ventures, incursion into neighboring Chad last winter and massive stockpiling of Soviet weapons -- has prompted calls for his ouster by Egypt and Sudan and ominous warnings from the Reagan administration stressing a campaign against terrorism, including the expulsion yesterday of all Libyan diplomats from Washington. The vehicle for an overthrow seems to exist already in a widespread network of exiled Qaddafi opponents.

And yet, Qaddafi has given his potential adversaries powerful motives to leave him in place. Despite his frequent denunciations of American "imperialism," he has left intact the operations of U.S. oil companies and the flow of oil exports that has made Libya America's third-largest supplier. For the Soviet Union, he offers oil supplies and a lucrative trade in weapons that is helping the Soviets gain strategic influence in the Mediterranean region.

Despite a reported $12 billion arsenal of Soviet-supplied weapons and 5,000 Warsaw Pact military advisers, Qaddafi is viewed as unlikely to extend his military incursions beyond Chad. His 60,000-man armed forces, with more than a tenth of their manpower in Chad, are said to be too strained logistically in that country to do much more than consolidate their positions and yet his threat has helped justify military buildups and requests for U.S. aid by Egypt, Tunisia and Israel.

Furthermore, although Libya's internal politics are not easily gauged by outside analysts, the volatile 43-year-old colonel seems to have neutralized much potential opposition by balancing attacks on traditional institutions and his opposition with a government that has spread some of the wealth of petrodollars.

Diplomats and analysts interviewed in Cairo, Khartoum, Beirut, Tunis, Paris and Damascus seem to agree that Qaddafi has been so successful in rooting out Libya's old economic elite since his 1969 takeover that an Army rebellion is the most potent threat to him, Washington Post correspondent Jonathan Randal reported.And yet, a rebellion by an Army brigade last August in Tobruk was easily crushed by Qaddafi's forces and East German security troops.

Members of the former elite, including a number of former high officials in Qaddafi's government, form the backbone of the exiled Libyan opposition. Scattered through Arab countries and European capitals, the exiles have formed three multipartisan organizations that have published anit-Qaddafi literature abroad and, since last fall, reportedly slipped some of it into Libya.

Even the most hopeful of these dissidents say, however, that a successful assault on Qaddafi must be founded on both international unrest and the promise of tacit support, at least, from the United States. For now, both of those necessary catalysts are in doubt.

The man who Qaddafi's friends and foes all seem to agree is his most formidable Liby anopponent, former Libyan ambassador to India Mohammad Mugarieff, assured a U.S. interviewer recently that Qaddafi "has lost all factors of credibility and legitimacy" and seeks only to "remain in power for extra days."

In unbroadcast comments to ABC news, Mugarieff, now believed to be in Sudan after a visit to the United States, referred to what he said was protection of Qaddafi in 1969 by the U.S. Central Intelligence Agency, however, and called on the United States "leave us alone in our struggle against this man," according to a transcript of the interview.

"If they can't do anything helpful," Mugarieff said of Americans, "then at least they should take no sides and leave the Libyan people to decide their own future, their destiny with this regime."

Other exiled Libyans, including supporters of Maj. Abdel Moneim Hony, a close Qaddafi associate who defeated in 1975 and now leads Libyan emigres in Egypt, say they have asked the United States what it would do, if anything, to help neutralize or overcome the Soviet Bloc security forces supporting Qaddafi.

For now, U.S. officials will not confirm contacts with the exile organizations, and the Reagan administration has yet to establish a clear position on Qaddafi's opponents. But significantly, much of the initial maneuvering by both Qaddafi and the new administration has centered around the five American companies that buy over half of Libya's output.

Qaddafi summoned executives of the oil companies to a meeting in February during which his chief aide called for their pressure on Reagan for better relations with Libya. The oil companies were scheduled for a high-level State Department meeting on Libya this week, although the meeting was later canceled.

Even if the United States encourages the exiled Libyans, some analysts doubt that internal disenchantment with Qaddafi is as high as his opponents claim.

One diplomat who was in Libya when Qaddafi took power in 1969 and has returned since observed that Qaddafi has pacified much of a country that might otherwise resent his agrarian-reform program and other revolutionary changes by using oil profits to produce "a welfare state."

"For a guy who was shoeless 15 years ago, Qaddafiis nothing less than a messiah when he allows that man's son to earn a graduate degree from a good Amderican university on a government scholarship," he said.

Qaddafi has felt threatened enough abut the opposition, however, to launch attacks on it both at home and abroad. Eight Libyans were murdered in London, Rome and Athens last year, and there were attempts on others, including Mugarieff.

Libyan officials deny government responsiblity for the assissinations, but Mugarieff and other exiled leaders have been condemned to death by Libyan "people's courts." Meanwhile, the threat of attack has served to keep the network of dissidents abroad scattered and wary.

In addition to Mugarieff and the Egyptian-based Hony, some of the most prominent of these dissendents include Mahmoud Suleiman Maghrebi, a former Esso Corp. petroleum engineer who served as prime minister under the first Qaddafi revoluntionary government in 1969 and later as ambassador to the United Nations and England; Ahmed Ibrahim Ahwas, a former Libyanambassador to Guyana, now in Morocco, and Omar Yahia, a Libyan businessman living in Oman who has also been condemned to death in Libya.