ALL IN ALL, it hasn't been a very good month for dictators.

When Ferdinand Marcos arrived in Hawaii last week, he looked like most other visitors to the island paradise. Bowing to have a lei draped around his neck on an airport tarmac similar to the one Benigno Aquino was gunned down upon, all that the former Filipino strongman needed to complete the costume of a stereotypical vacationer was an instamatic camera dangling from his neck.

But, of course, Marcos was no typical elderly vacationer and his stay on the Hawaiian Islands will be no ordinary sojourn. As Baby Doc Duvalier had recently done in Haiti, Marcos had just bid a hasty adieu to a people and a nation he had ruled for many years with an iron fist and a greased palm.

However, both of these recent happy events will soon pose some potentially embarassing problems for the United States. Both retired despots agreed to hang up their spikes only after the Reagan Administration promised them safe passage out of their former playgrounds. And both men and their groupies naturally assumed that they would have at their beck and call the fortunes they had plundered during their years in public service.

According to U.S. customs officials in Hawaii, Marcos arrived in Honolulu with a few million dollars in cash and several million more in jewelry, art and other valuables hidden in boxes of Pampers diapers. U.S. customs laws demand that anyone bringing in more than $10,000 worth of currency make a formal declaration of just how much they have.

MARCOS, WHOSE ANNUAL salary as president was $4700, has always denied charges of corruption by claiming that he amassed his fortune from a lucrative law practice. Right. Marcos undoubtedly gained much of his fortune by dipping his hand into the cookie jar of 20 years of American "economic and military aid."

A Filipino commission estimated Tuesday that he and his friends may have as much as $10 billion invested in Western banks and real estate. When the final decision was being made by Marcos to either abdicate or fight the demonstrators outside the Presidential palace, Imelda Marcos reportedly asked her husband, "If we wipe them out, what will happen to our assets in the U.S.?"

Although the former Haitian honcho's wealth is apparently not as great, Duvalier and his entourage don't exactly have to travel on the budget plan, either. While the Mitterand government decides what to do with him, Duvalier and his family are currently holed up in a posh Parisian hotel that wants them out. "They're bad for business," said the manager.

But the Reagan Adminstration doesn't have the luxury of operating in the moral climate of hotel managers. Filipino law--written by Marcos and his cronies--places strict restrictions upon flights of capital and valuables out of the country. The new Aquino government will ask for it to be returned.

IT WOULD BE wrong for the U.S. to hang Marcos and Duvalier out to dry. For one thing, this would be unfair to men who, like it or not, were for many years "our S.O.B.s" in the fight against the Evil Empire. But, more important, it would send the wrong message to other despots the U.S. might one day like to spirit out on the first transport out of town. With the assurance of safe passage out of Manila and asylum in the U.S., Marcos at least chose to leave without shedding blood. If the U.S. were to now leave these men out in the cold,it would make it tough in the future to get other miscreant leaders to abdicate without trying to hang on until the bitter, bloody end.

In the case of Marcos, nothing the U.S. can do will leave him high and dry. Even if the government seizes the Manhattan properties that earns him an estimated $75 million this year, Marcos has plenty of cash stashed away in untouchable Swiss bank accounts. So it's unlikely that he'll end up like Nguyen Cao Ky, another despot America once supported. The flamboyant Prime Minister of South Vietman during the glory years of 1965-67, now owns and operates a liquor store in California.

Marcos is old and sick and a long-time ally of the U.S. He and Imelda shouldn't have to open a Ma and Pa shop in order to support themselves. But that doesn't mean he should be allowed to go on living like a king after the revolution has knocked him off the throne and out of the palace. The cash and valuables they spirited out last week and the property they bought with American aid should be confiscated and returned to the Filipino people. And if Marcos still feels he's strapped for cash, well, I'm sure he can always get a guest gig on Magnum P.I.

But America should hold its collective nose and allow the Marcos's and Duvalier's of the world to finish off their sad, little, miserable lives in relative comfort. If that's the price we have to pay so as not to discourage other dictators from one day booking one-way pasage on an Air Force red-eye, so be it.