America's grand gesture toward Somalia has officially ended.

Except for 50 Marine U.S. Embassy guards and a few stragglers, the last of the U.S. troops dispatched 16 months ago with such flourish to implement Operation Restore Hope marched off the hot beaches of Mogadishu Friday.

For months now, these troops have languished in their compound at the capital airport and in various sites around the country. They ventured out only in helicopters, or in force, with weapons bristling behind steel plate.

Today Mogadishu is a lawless city full of gunmen and bandits. It's much the same as it was when these troops arrived in December, 1992, full of expectations that they might help put it right. Many of them expressed that hope right on the beach, still wet from the surf. But, at the end, they were forced to hunker down behind razor wire strung out to shield them from the animosity that grew on every side.

As they leave, it is doubtful many of those young men will glance back with warmth toward that ruined paradise where all their good intentions turned sour, their predisposition to assist the Somalis was transformed into plain disillusion. Even now, at certain times of day, when the sky is the right lemon color, Mogadishu can recall those days when it was a more or less well-ordered Italian colonial outpost, a pleasant enough place where flowering bougainvillea enveloped and decorated tiled verandas, all despoiled now.

Is their disappointment justified? Not entirely. The GIs were told they were sent to help feed a starving people. They were. They did. It is the main point of the story of the Somalia intervention -- and it is a success story, if not entirely so.

One might say the mission was a success and a failure in equal parts, but the success of it is almost always overlooked.

The success of the U.S. mission in Somalia is evident over at the Fayette Street headquarters of the Catholic Relief Agency, where plans are being drawn for the agency's own withdrawal from Somalia. They have worked themselves out of a job. They are turning their attention to other, incipient catastrophes elsewhere in the Horn of Africa.

Said Ken Hackett, head of Catholic Relief: "We went in on the relief phase, stayed for the rehabilitation stage. We went through three cycles of planting. The local systems are almost back up to where they were prior to the bad times of late '91 through '92.

"There is more trade, and commerce has picked up. We don't see our relief role there much longer."

Most of the other agencies that went in several years ago to confront the famine have withdrawn, some but not all, like Catholic Relief, because their missions are complete.

Mr. Hackett is not suggesting all is right in Somalia. Banditry has increased. Here and there, clan tensions are heating up. Three weeks ago, the agency had to implement a brief emergency food distribution in a few isolated places where crops failed.

And there are reports of a cholera outbreak near Mogadishu and Kismayo. If this worsens there could be a lot of death. If the clan rivalry is not soothed, all-out warfare might flare again. Somalia could slip back into famine.

But there is no certainty it will, and in the absence of the inevitability of catastrophe one can be forgiven for presuming a more benign outcome. As hopes go, it is not an extravagant one.

Much good work was done by agencies such as Catholic Relief, the Red Cross, even the United Nations. Children were rescued, people returned to their home territories, seed was planted as the donated food was distributed. Finally, crops were harvested and Somalia began to mend as its people ate the produce of its own soil -- sorghum, for the most part.

The doing of all this was facilitated by the presence of the GIs and other U.N. troops. This week the protective mission will be turned over to large contingents of Pakistani and Indian troops.

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When and how things went wrong with the U.S. mission in Somalia is no secret. The turn for the worse came about six months after the arrival of the GIs, when the mission was enlarged from guarding food convoys to a direct military engagement with the militia of Gen. Mohamed Farah Aidid, the country's pre-eminent warlord. What had been a humanitarian mission at that point became a military operation.

The shift occurred after the ambush and killing of 24 Pakistani peacekeepers last June 5 by forces thought under General Aidid's control. The commander of U.S. forces in Somalia, Adm. Jonathan Howe, decided that this could not go unpunished if the United Nations were to retain credibility. And so, General Aidid was ordered arrested. He was pursued, a price of $25,000 put on his head. The aim was to snatch him, spirit him out of the country and try him for the killing of the Pakistanis. He was to be removed as a factor in Somalia.

During the period of search and pursuit, 18 U.S. troops were killed and nearly 80 wounded in a single firefight. It occurred on Oct. 3, last year. A U.S. helicopter was shot down. The American dead were dragged through the dust. It was all over television.

As efforts to capture the warlord were pressed, fruitlessly, support for the overall mission in Somalia withered in Congress. Then, in response to that, the strategy was reversed again: General Aidid was left un-pursued, even declared a prospective part of the ever-elusive solution to Somalia's disarray, no longer part of the problem.

At best it was humiliating. Washington had sent its elite troops into Somalia expecting that they would shortly roust the fugitive Somali leader, and they failed.

It is not hard to understand why Admiral Howe would go after General Aidid. Or why he would try to disarm the militias through numerous lightning raids on their secret armories. The killing of the Pakistanis was a monstrous provocation to the United Nations. Also, Mogadishu seemed to support the argument that where weapons circulate in great number and law enforcement is lax, there will be violent deaths in profusion.

But it is also hard to avoid the feeling that the decision to remove General Aidid reflected a deep hubris, a reflex natural enough perhaps to those who conceive the strategies of a superpower. This inclination derives from the conviction that because the United States is a rich country with vast and sophisticated military and technical resources, it can arrange events as it sees fit in a poor and primitive country with only rudimentary devices of self-defense.

Former Sen. J. William Fulbright many years ago described this syndrome as the "arrogance of power," a phrase that became emblematic of the Vietnam era. It is not new to the American experience. The puzzling question that its appearance again raises is why successive generations of policy-makers never seem to learn from their predecessors' mistakes, or even from books.

Political philosopher Richard E. Flathman suspects it might simply be a way of thinking that comes with living in a superpower. Dr. Flathman, at the Johns Hopkins University, thinks Americans "have a residual belief from the Cold War that when we are alerted to serious problems that our state ought to do something about it."

He calls this "self-privileging," and finds little justification for it.

"If there is a generalization we can make, it is that we have a residual belief in our omnipotence. There never was any basis for this. Any one of the innumerable interventions we have undertaken have had the possibility of failure. [Many have failed.] It is amazing to me that we really haven't learned the lesson of Vietnam, that local circumstances don't admit, don't allow, themselves to be regulated by our power."

Another issue, besides the one of imperial presumptions, has been pushed to the surface in Somalia. It grows from the question of why we went there in the first place.

Was it a simple humanitarian reflex on the part of President George Bush to the famine? Possibly.

But Somalia is, and was, a dangerous place. Mr. Bush knew that, and it is exceedingly rare for countries to put their troops into harm's way for strictly humanitarian reasons. There was no evident national interest being served by the decision, nothing strategic, nothing commercial.

Some students of international affairs think the Somalia intervention was almost entirely media-driven. They are apprehensive that this trend is growing, wary because such actions preclude more deliberative, cooler decision-making.

Dr. Flathman is one of them. He suspects the media played a part in encouraging the Somalia intervention.

"There are a whole lot of disagreeable, very repugnant happenings going on around the world," he said. "The question is how our attention gets focused on any one of them. We are really not talking about any kinds of national interest in Somalia or Bosnia. Something has to explain why we make the choices we do. In the absence of any clearly decisive explanation, I don't know what else to look to."

With regard to Bosnia, Michael Clarke, head of the Center for Defense Studies at King's College in London said last month he believed the only reason the Clinton administration was moved to threaten the Bosnian Serbs surrounding Sarajevo with air strikes was "all those pictures from the Sarajevo market," which was struck by a mortar shell Feb. 5. Sixty-eight people died. It was all over television.

The media factor is not new in politics. Press reports of overseas crises have always been weighed by governments because such reports moved public opinion. Consider the Hearst newspapers' role in fomenting the Spanish-American War. But the arrival of television has intensified those public responses. Accordingly the pressure has been heightened on those who make major decisions for governments.

It is not certain whether Mr. Bush's motive was pure public relations or one of sympathetic altruism (not bad in itself), a reflex stimulated by the media reports of the famine. It is possible he was lulled by the smooth success of U.S. power in the Persian Gulf war into thinking it could be applied easily in Somalia.

But whatever the motive, the whole experience of Somalia was another lesson in the education of a nation. Once again it revealed the limitations of U.S. power. Maybe one day the lesson contained in that experience will finally be learned.

Richard O'Mara is a reporter for The Baltimore Sun. He was in Somalia in August 1992 for two weeks at the famine's height, and returned to be on hand for the arrival of the U.S. troops in December 1992.