The 1981 threat by Libya's leader, Muammar Qaddafi, to assassinate President Reagan may have resulted from Colonel Qaddafi's misreading of American pressures against him, according to top US intelligence experts.
Qaddafi's life and political survival were in no danger from the United States, the experts say. But, they add, a combination of threatening remarks from American officials, the misreporting of secret American attempts to curb Libyan influence in Africa, and an aerial shootout off the Libyan coast between US Navy and Libyan fighters was apparently what caused Qaddafi to threaten Mr. Reagan's life.
The experts, who request anonymity, have no doubt that the threat from Qaddafi was real. They say they now believe that the ''hit teams'' launched by Qaddafi never reached the US. But some of their members were reported to have arrived at undisclosed locations on the North American continent, presumably in Canada or Mexico, late last year.
In the summer of 1981, a series of press reports concerning secret American actions against Libya created a stir in Washington. The problem was that the first reports on the subject seem to have been misinformed.
According to one specialist on the subject who was actively involved at the CIA at the time, the initial leaker may have been a congressman or aide who, unlike some others, had not taken the trouble to get fully briefed.
The reports came at a time when CIA director William J. Casey was under fire from senators because of past business dealings and the controversial appointment of Max Hugel, a businessman with little experience in intelligence matters, to run the CIA's covert operations. The atmosphere was one in which everything Mr. Casey did was questioned.
Newsweek magazine, on Aug. 3, 1981, reported that Mr. Hugel had presented the House Select Committee on Intelligence with a costly and large-scale plan to overthrow Qaddafi. According to Newsweek, committee members thought the plan implied that Qaddafi would be assassinated. The committee supposedly sent a strong letter of protest to Reagan.
But according to a source who was fully informed on the matter, the target of the secret operation was not Libya but ''Libyan influence'' in Mauritius, an island nation of just under a million people located off the southeast coast of Africa. The letter of protest from the committee went not to Reagan but to Casey.
By this time, however, the public record had become thoroughly muddled. Yet another misinformed source had confused Mauritius with Mauritania, the two names being vaguely similar. That source triggered yet another press report, this one in the Washington Post, saying that the CIA's target was Mauritania, a country located on the northwest coast of Africa. Almost unnoticed, the Wall Street Journal got the Mauritian target right.
The White House denied any plot against Qaddafi. But given the Reagan administration's earlier public and private statements about Qaddafi, not too many people would have been surprised if such a plot had been conceived.
At one point in the spring of last year, for example, then-Secretary of State Alexander M. Haig Jr., in an off-the-record comment in an interview, remarked that Qaddafi was ''a cancer that has to be cut out.'' A reporter for the New York Daily News found out about Mr. Haig's remark and published it.
But, according to one intelligence expert, when administration officials examined the options, they discovered that Qaddafi might well be overthrown some day without any help from the US. They found that dissent was strong in certain sectors in Libya, and that in the Army there were officers who resented being sent off on costly adventures to places such as Chad and Uganda. They also knew that a number of coup attempts had already been attempted against Qaddafi. The administration decided to work to help thwart Qaddafi's designs outside Libya and to raise the cost to Qaddafi of his overseas adventures.
The mix-up in the press over Libya, Mauritania, and Mauritius might have added up to little more than an amusing farce to shake Washington out of its 1981 doldrums. But two professional intelligence analysts say that the misinformed leakers may have created a boomerang problem of mammoth proportions. They suggest that talk within the administration about putting pressure on Qaddafi and the published reports concerning a possible secret plan aimed at overthrowing the Libyan leader, combined with the impact of the US-Libyan air battle over the Gulf of Sidra on Aug. 19, 1981, in which US Navy jets downed two Libyan planes, probably led Qaddafi to threaten Reagan's life. They say that at one point late last year, Qaddafi made statements to the effect that he was out to get Reagan. A defector, who claimed to have been directly familiar with orders given by Qaddafi to assassinate Reagan, was one of the sources of information on this subject.
In the end, Qaddafi apparently called off his hit teams. Insiders say that some as yet undisclosed secret US-backed actions aimed at curbing Qaddafi's operations in Africa met with moderate success. But it is the recent oil glut as much as anything that has damaged Libya, by cutting Qaddafi's oil revenues.
In some cases, overt, rather than covert, actions have hurt Qaddafi. These have included the US oil embargo and diplomatic moves aimed at isolating the Libyan strong man. Most important, a number of black African nations have rejected Qaddafi's attempts to chair a summit meeting of the Organization of African Unity (OAU) in Tripoli. Qaddafi support for insurgents in Chad was the main reason for a recent second collapse of the projected OAU summit.
Some American analysts now say that what was done to counter Libyan influence in Mauritius might have been better done through open means, such as support given through a political foundation rather than through the CIA. The United States, while aiming the CIA at a mouse (Mauritius), may have ended up stirring a tiger (Libya).
In Mauritius, the mouse that didn't roar in the end at the US, a certain degree of businesslike equanimity seems to prevail. During a visit to Washington in September of this year, Paul Berenger, the country's finance minister and secretary-general of its ruling Mauritian Militant Movement (MMM), indicated that he would like to forget past frictions and get down to dealing with serious problems like the sugar quota the US had slapped against his country.
Mr. Berenger, a youthful, articulate Franco-Mauritian, has been depicted by his political foes as a dangerous radical. It was apparently this as much as anything that led the Reagan administration to try to help keep him and his movement out of power during last June's elections in Mauritius. Officials in the government of then-Prime Minister Sir Seewoosagur Rangoolam claimed that the MMM's election campaign was financed by Libya, a nation with strong ties with the Soviet Union. An American intelligence analyst said that the US was ''certain'' that Libya was involved.
The MMM further alarmed the US by vowing to mount a diplomatic offensive aimed at securing the Mauritian claims to the Chagos Archipelago, which includes the key US military base on the Indian Ocean island of Diego Garcia.
According to a New York Times report from Mauritius on June 9, 1982, the prime minister's backers hoped to use television to turn the election tide against his opposition. The Times said that they turned for imported media expertise to a group headed by a US media consultant. A series of television spots portrayed Sir Seewoosagur as a world statesman.
This triggered charges from Berenger's party, which asserted that because of the prime minister's relatively accommodating stand on the issue of Diego Garcia , the CIA brought in media consultants to assist him. The consultants were rumored to be operating from the neighboring French island of Reunion.
The prime minister's office, for its part, released a set of documents in Arabic supposedly describing commitments that Berenger had made in exchange for documents ''crude fakes,'' pointing out among other things that the eagle on what was supposed to be a Libyan letterhead was pointed the wrong way. Sir Seewoosagur called Berenger a Communist.
In an interview with the Monitor during a visit here in September, Berenger did not deny that his country sought above-the-board financial aid from Libya and from whomever else it could get it. But he also said that Mauritius valued its ties with Western-supported financial institutions.
''Once upon a time, we were supposed to be pro-Soviet,'' said Berenger. ''But people forget that we have regularly taken a stand against the Soviet invasion of Afghanistan. Before that, we took a stand against the invasion of Czechoslovakia.''
An American intelligence expert, meanwhile, confirms that the Reagan administration had sought to bolster the election chances of Sir Seewoosagur by quietly providing ''low-level'' support. But American support failed in a spectacular way: Berenger's movement won the June 11 election in a landslide. Sir Seewoosagur's party lost all its parliamentary seats. The same intelligence expert said that the State Department, not the CIA, conceived of giving a little help to Sir Seewoosagur. But State Department officials now seem to be pleased with Berenger's pragmatism.
In the interview, Berenger was diplomatic about the allegations of a CIA role in the election campaign.
''Some people say that the CIA was involved in the electoral campaign,'' he said. ''. . . Our opponents' campaign was organized by American citizens.''
''But they made such a mess of it, we would almost welcome them back next time,'' he said.