Ex-president Duvalier of Haiti and ex-president Marcos of the Philippines both fled their poor countries as rich men. Both had taken advantage of their period in power to build up vast foreign fortunes. After their fall, both were granted residence in rich countries, and, despite legal challenges, both are now able to enjoy their ill-gotten gains.

Other Third World dictators are undoubtedly still building up their foreign wealth against the eventuality of one day being forced to flee their countries. The West needs to consider now whether it is going to provide them with the same comfortable retirement that it is allowing Duvalier and Marcos.

The case against refusing to provide fleeing dictators with a sanctuary is clear. They, too, are human beings whose human rights are unlikely to be respected otherwise once they fall from power. In some cases the West has taken advantage of their friendship and owes them a decent retirement. Above all, without the assurance of a comfortable exit, the chances of a bloody fight to maintain their rule will be vastly increased.

But the case against continuing to allow ex-dictators to enjoy their illicit wealth is also overwhelming. Not only does it offend moral sensibilities, but it encourages dictators (and conceivably others) to contribute to capital flight. In a few countries, apparently including the Philippines, the personal hoarding of the rulers has been a major component of the capital that has sought a safe haven abroad. And capital flight is a major cause of the Third World debt problem and, thus, of the austerity that so many countries are still suffering.

A better approach would be to offer ex-dictators sanctuary, but on the condition that they renounce any wealth above a sum adequate to prevent their becoming a charge on the state that takes them in. Let them keep a million or two, but let them enter a Western country only on condition that they return any wealth above that to their own country.

Enforcement of such a requirement ought not to be an overwhelming problem, because a natural and potent sanction for noncompliance exits. Proof of intent to evade such a requirement, either by seeking to conceal assets or by giving them away to anyone other than residents of their country of origin, should be grounds for repatriation. Given the choice between a secure existence in modest comfort and the risk of hanging onto assets that could never be enjoyed because this would advertise their crimes, it would be odd indeed to opt for the risks of evasion.

It is possible that the U.S. legal system is going to provide a partial substitute for a policy of conditioning the right of residence on repartriation of capital. One hopes that the Philippine government succeeds in recovering through the courts much of the wealth spirited away by the Marcos family. But at best, such a process will be slower and more expensive than an administrative requirement on arrival in the United States would have been. At worst, the courts may rule in favor of the Marcos family, as happened in Honolulu recently when the Customs Service was ordered to return $7.6 million in jewelry and currency seized from the Marcoses when they landed in Hawaii in February.

The fact that relying on the courts -- and in this respect American courts are far more promising than those of other potential Western sanctuary countries -- is inevitably less certain is of special significance. It means that there will be little effect in deterring other Third World rulers from building up their foreign nest eggs. Indeed, it might encourage them to increase their foreign placements so as to be able to diversify them and be sure of keeping some even if others are sequestered by the courts.

There are some things that can be done more efficiently by government than by private initiatives in the courts. Deterring corrupt Third World rulers from lining their pockets at the expense of their citizens, so as to secure their future in the event of being forced to flee their country, is a case in point.

This proposal would make no more than a modest dent in the overall problem of capital flight, but it should not be dismissed on that account. Not only is every little help worth having, but it would also signal Western support for Third World democracy and Western condemnation of corruption in a clear and tangible way.

The writer is a senior fellow at the Institute for International Economics.