IF THE FEARLESS fragment-finder, Indiana

Jones, succeeded today in crating up and shipping to this country the mythical "lost ark of the covenant," whose pursuit has preoccupied moviegoers this summer, probably its arrival would occasion not further mayhem but only confiscation by the U.S. Customs Service. Custom's seizure early this year at Dulles Airport of valuable artifacts shipped from Peru reflected the government's prevailing approach to questionably imported merchandise. A grand jury in Alexandria has been investigating the matter, but our interest lies in the general problem of importing art works, not in any possible allegations of wrongdoing that might emerge in this instance.

Throughout history, the conquest of groups and nations--whether by force of superior arms or dominant culture--often has been accompanied by wholesale transfers of art and artifacts belonging to the vanquished to the control of the victors. In this connection, it is worth recalling that a number of countries (mainly in the Third World) that now protest the taking of their archaeological heritage over the last 150 years by the cultural "viceroys" of the imperial West had themselves engaged in such deliberate pillaging of their less-powerful neighbors in the past. The problem, in short, was not created in modern times or by Western countries, much less by the United States, and good remedies are not always easily found.

What should be done? Apparently a 1972 American law restrains those who try to traffic in a more massive artifact, one whose export had been proscribed by its home country. In the future, it may be more difficult to transport across the Atlantic (stone by stone) an edifice such as Manhattan's magnificent Cloisters, though "London Bridge" (a recent and legal "import") has flourished in its Arizona rebirth. As for smaller items--like the pre-Columbian objects now so popular in this country--no statute currently bans their illegal exchange authoritatively, despite a 1972 U.N. Treaty, which this country signed, that set criteria for international trading in these artifacts.

Up to now, Congress has avoided passing legislation putting the 1972 treaty into effect, so the Customs Service plunged ahead into this legal no- man's-land wielding the provisions of the National Stolen Property Act. Customs argues that, even if dealers purchased objects lawfully, the artifacts themselves can be considered "stolen" if they are imported into the United States in violation of foreign laws banning their removal.

So, thus far efforts by the Customs Service to regulate the booming business in art objects (at least, the smaller ones) has been based upon a law not designed originally to achieve that objective. This is not a good way to do business. And you have to ask: must every foreign claim to absolute statutory control of a national aesthetic heritage--no matter how bizarre, broadly defined or retroactive --be accepted at face value by American courts? Obviously not. Still, considering the past plundering engaged in by acquisitive archaeologists and collectors, Congress should act promptly to either ratify the 1972 U.N. treaty or otherwise clarify the conditions under which customs agents can confiscate foreign art works of clouded title.