LIBYA SHELL-SHOCKED The colonel missed the party

Each year since Colonel Muammar Gaddafi seized power in 1969, Libya has celebrated the day that he expelled U.S. military personnel from Wheelus Air Base, outside Tripoli. It was widely assumed that Gaddafi would use last week's 16th anniversary of the occasion to make his first live public appearance since U.S. warplanes attacked Tripoli and Benghazi last April. Western reporters were invited to Tripoli and advised to expect a major speech. Gaddafi never turned up. An apathetic crowd of 2,000 Libyans who gathered in Tripoli instead heard a harangue, apparently videotaped earlier, that raised doubts about how much longer the colonel can remain as ''leader of the revolution.'' The nearly two-hour televised address showed an exhausted-looking Gaddafi fidgeting in his chair and speaking in a hoarse voice. His diatribe against the U.S. and Western Europe was devoid of the fiery rhetoric that he has employed in the past to whip crowds into a frenzy. Among other things, he reportedly discussed a controversial meeting with William Wilson, the U.S. Ambassador to the Vatican who later resigned. The lackluster performance reinforced a growing belief that Gaddafi has not recovered from the shock of the April 15 bombing raid. The attack, and the pitiful defense put up by the Libyan military, exposed the emptiness of Gaddafi's threats. Said one foreign resident of Tripoli: ''Libyans were always told what Gaddafi would do when the Americans came to attack. But when they came, all this beautiful talk was for nothing.'' There has been speculation that the U.S. raid forced Gaddafi to share power with the four other members of Libya's ruling Revolutionary Council. Gaddafi may also have less support from his principal ally, the Soviet Union. A delegation from Moscow that had been expected to attend last week's ceremonies failed to show up. Such a conspicuous absence strengthens the suspicion that the spark has gone out of Gaddafi's revolution.