There is something undeniably refreshing to the foreign policy of Ed Clark, the Libertarian Party presidential candidate, and I don't mean merely that he makes the too-good-to-be-true offer to deliver more real security than we've enjoyed since World War II at greatly diminished risk and cost.

It's that he tries to draw the hard lessons from the widespread disillusionment felt for our post-war policy of active internationalism: it has carried heavy costs in many dimensions and left an awful lot of Americans feeling that, for all the country's exertions, the world remains in unacceptably dangerous and ungracious place.

The three main candidates, of course, have variations on one answer -- a promise to conduct the old internationalist policy more effectively. Clark's answer is his own and it is, if nothing else, logical: if engagement is the problem, disengagement is the solution. He takes to the end the road that liberals leave halfway.

Clark would abandon pursuit of strategic superiority or of military balance for simply "strategic stability" and "basic security." He would phase out all our overseas commitments and end our activists diplomacy. He would limit the Pentagon to the means (about $90 billion worth) he deems necessary for an adequate territorial defense. "We're not entitled to risk our survival for that of others," he said in an interview the other day.

Clark arrived at his views, he said, by a process that began when, as a student, he saw in one French cemetery the graves of 40,000 soldiers who had died in one battle of World War I. He came to think that a kind of supernationalism, "state worship," by which the state grows and is praised and is constantly given more functions and powers, leads nations to wars, the ultimate disaster. "Any government strong enough to solve our social problems can destroy us," he summed up.

Few students of modern history would fail to acknowledge that Clark is on to something profound and true -- something familiar but nonetheless inadequately understood. Why did those 40,000 Frenchmen offer their lives in a battle that moved the front first three miles one way and then three miles the other? What do we mean by demanding to be "No. 1"?

But "state worship" is part of the answer, not all of it. Root it out as best you can and you still are left, I think, with a world that is considerably more troublesome than the basically optimistic Clark takes it to be. He comes out at a place that others would call isolationism -- he prefers to call it neutrality. His doctrine offers a convenient escape from hard choices to those less fastidious than he.

I am leery of the Clark prescription, elaborated in a "white paper" drafted chiefly by Earl C. Ravenal, a Georgetown professor and former Pentagon aide. He says his policies would produce a happy, or happier, result than a continuation of the old. Why wouldn't American disengagement have just as good a chance of producing disaster? He expresses a readiness to live with whatever results did come about, but I and lot of other people would not be ready to live with some conceivable results. Consistency comes easily to Clark, a relentless practitioner of a particular ideology. I want some room to bob and weave.

Where he is best, it seems to me, is in understanding the nature of the world in which any American foreign policy must work. The premise of internationalism -- to Clark, interventionism -- is that the world is finally a manageable or manipulable place where Americans can make a telling difference -- whether it is by asserting American values, American skills or American power.

Clark accepts what I believe to be the truer condition: that the world is getting stickier all the time. Temperamentally as well as intellectually, he seems to be at ease with a condition of diffusion of power. Indeed, he accepts it to a fault: to the point of self-paralyzing modesty. But the message, especially in these superheated times, is sound.

There is something else about Clark. Though his judgment can be challenged, he has at least thought through foreign policy and fitted ends -- for him, the avoidance of war and the defense of the homeland -- to means, to the kind of diplomacy he envisages and the sort of resources he would invest in national security. Not for him the asserting of ambitious purposes that the country cannot in fact uphold, nor the spending of resources for which no reasonable policy goal can be framed. This is a model of the discipline that ought to be demanded of all the candidates.