LIBYA'S Col. Qaddafi seems to have decided to remove the thousands of troops he had ordered into Chad, on his southern border, last year. It is always risky to speculate on what moves this curious figure. In recent months, however, the United States has been escalating its expressions of concern over his international banditry. French President Mitterrand had devised a new diplomatic plan, holding out to Chad's president an alternative to dependence on Libya and encouraging other African states to expedite the dispatch of a peace-keeping force. The Libyan decision is neither fully consummated nor irreversible. In the best of circumstances, Chad will be left with the internal tensions that opened the way to Libya's intervention in the first place. For now, however, the specter of a muscular fundamentalist Islamic movement marching across black Africa appears to be suspended.

How dangerous is Col. Qaddafi? One school of thought holds that he is an overcompensating anti- imperialist capable only of an occasional assassination and that the West simply gives him ideas and advertises its own impotence by thinking he can do much more. But this is a patronizing and misleading view. His oil wealth, his Soviet connection, his feel for Arab and Islamic currents and his tactical boldness have made him a menace out of all proportion to his nation's underdevelopment and small size. Of the different countries that the Reagan administration has identified as villains on the international scene, none has established itself in that role more convincingly on its own. That is what is satisfying-- if it sticks--about the latest development in respect to Chad. Other nations, acting on their own judgment of Col. Qaddafi, sought to neutralize him in that corner at least.

One measure of this administration's concern is that it is now reported to have offered Egypt a military shield against the Soviet Union in the event that Egypt attacks Libya. This is an extraordinary offer, not least because it appears to delegate to another country the power to commit the United States to war. Fortunately, there are less risky and more defensible things the United States might do. One would be to cut back American purchases of oil from Libya, a development that market conditions currently facilitate. A second would be to call home the 2,000 Americans working in Libya whom Col. Qaddafi uses as a kind of shield. A third would be to find an effective way to remove the lingering and damaging suspicion that the ex-CIA men who have been helping him murder his enemies and conduct subversion still have some subterranean connection to the CIA.