DIFFERENT countries clearly have different preferences and abilities, as the renown of French perfume, Japanese cameras and American cowboy movies indicates. Perhaps it's time we took advantage of this fact to help relieve the growing strains in the Western alliance.

Much of the strain, after all, stems from clashes over how to divide responsibilities. The United States has long criticized its partners for inadequate military spending, while the allies complain that America has been ducking responsibilities in the area of foreign aid, which they believe can protect Western interests in the Third World.

NATO dropout France has led the way, with President Mitterand lecturing President Reagan last March that poverty, not Russians or Cubans, was the "father of revolution" in Central America and elsewhere in the developing world.

Similarly, Canadian Prime Minister Trudeau has strongly suggested that the United States has been blocking progress in the North-South "global negotiations" currently dragging on at the U.N. to restructure the world economy.

It is increasingly apparent that beneath these and other disputes is something simpler yet deeper than politics, ideology or even culture. The allies are diverging in their fundamental emotional and psychological preferences -- their tastes, if you will -- in foreign policy.

Growing numbers among the public and leaders of many allied nations have become uncomfortable with the idea that some use or threat of force may be necessary at some point to defend common Western interests. One detects among them a yearning to opt out of power politics, to exist, in Raymond Aron's words, as a community of "producers, not warriors."

Among Americans, on the other hand, there is disillusionment with what were seen as good-faith efforts during the 1970s to moderate the behavior of adversaries with summitry, trade and aid. In fact, except for the Marshall Plan, Americans have never bought the idea that economic aid can be a vital foreign policy instrument.

But assuming that the allies, for all their "army-phobia," still desire protection from the Soviets -- as the widespread European public support for remaining in NATO indicates -- and assuming that the United States, for all its recent bluster, really does not view military might as a panacea, why not rearrange responsibilities for the different elements of security to mirror different priorities?

Let alliance members establish a quid pro quo that would permit the United States to reduce its foreign aid in exchange for assuming a larger share of the alliance military burden. The allies could cut or freeze their military spending and channel more money into foreign aid.

Since defense budgets dwarf aid budgets, dollar-for-dollar swaps would be impossible. But precise numbers are negotiable, and even token shifts could greatly improve alliance relations by conveying the impression of each member shouldering the kind of burden its political preferences dictate.

The scheme follows easily from the economics-centered concept of "total security" that the allies have been pushing on Washington.

Western Europe's leading peace activists would likely be receptive to the idea. An "Open Letter to the American People" from West German disarmament advocates last June, for instance, explicitly criticized "gargantuan armament programs" for impeding "necessary aid for the Third World."

Concentrating increased allied foreign policy expense in nonmilitary ventures would also calm the nerves of those alarmed at the prospect of a heavily rearmed (and more independent) West Germany and Japan.

There may be less to possible roadblocks than meets the eye.

Would the plan founder on Congress' jealously guarded power to set U.S. aid and defense budgets? Or would the legislators jump at the chance to dump politically unpopular aid programs in the allies' laps? Would American industries dependent on exports to the Third World generated by aid programs be able to kill the idea? Or would their opposition be negated by economic interests that hope to benefit from a greater military buildup?

The swap might be opposed as well by allied defense industries, particularly strong in Western Europe. And allied governments might be reluctant to hand greater defense responsibilities to a country whose drift towards a nuclear war-fighting doctrine troubles them deeply. Yet Europe's arms makers would have great difficulty overturning a decision made by their nations' electorates.

As for the allies' misgivings about American military judgment, they would, by swapping responsibilities, justly forfeit a corresponding share of their power to shape Western military policy (just as the United States would lose much of its influence in the multilateral aid banks).

The United States and its allies would remain at odds over how best to manage relations with Moscow. But an aid-defense swap could remove the most explosive aspects of their dispute, the charges of betrayal and ingratitude and freeloading currently flying across the Atlantic and the Pacific, which are all too capable of shattering Western unity even before political differences decay.