THE WORD IS OUT: Iwo Jima is going to be a base again. A Japanese base.

It burns in our memories like a pure flame from a simpler if bloody past, that small island one-third the size of Manhattan which played host to the mutual slaughter of Americans and Japanese, the costliest battle in terms of time and property of World War II: 21,000 Japanese defenders dead, 25,000 Marine Corps casualties in little more than a month, for the ownership of an isolated pock of ash and weeds 5 miles long and 2 wide. It was the most real repository of heroism, a place where Fleet Adm. Chester Nimitz could reflect that "uncommon valor was a common virtue" among American fighting men, a scarred island whose cracked earth breathed sulfur fumes as if its insides had gone wheezing and rotten, and whose topography provided perhaps the most inspirational military pose a camera has ever caught, transferred into a statue that has become a shrine. Iwo Jima.> We paid for it, every bloody square inch, with the agony of dying men and the undying tears of those they loved, for the good of democracy and all things American.

And now if you stand on the invasion beach and stare up toward the bald height of Mount Suribachi, chances are your view will be obstructed by yellow Japanese tractors that scoop away the loose black sand so that cargo ships can unload. And if you climb the steep hill and peer down its backside you will see earth movers gouging out dirt to use for fill as they expand the runway -- Japanese earth movers, building up a runway that will soon, if plans go through, house Japanese aircraft -- fighters, antisubmarine patrol planes and helicopters.

The remilitarization of Iwo Jima will no doubt cause strong emotions to flow among many Americans, just as the return of the island to Japanese dominion did 13 years ago. And, in many ways, the prospect of Japanese combat forces there provides a metaphor for the ambivalence which we and the Japanese themselves feel about the thought of a rearmed Japan. On the one hand, it has become evident that the imbalance in defense responsibilities between our two countries must be remedied, or at least adjusted. On the other, it is not clear what missions Japan should be allowed, or forced, to perform. And at the bottom of it all is an underlying tension, a question of whether and in what manner the United States should intrude into the internal affairs of a country which has grown in the last three decades from its protected child into its greatest economic competitor.

> It is often stated -- correctly -- that the Japanese are getting a free ride in defense matters, having allowed their economy to burgeon without paying the price of protecting their trade routes. The Japanese gave spent less than 1 percent of their gross national product on defense since the late 1960s, while the United States has spent between 6 and 10 percent of its GNP on defense during this period. The average American taxpayer spends $759 a year on defense; the average Japanese, $98.

The Japanese military consists of a localized "self-defense force" (JSDF) whose combined air, maritime and ground components total scarcely a quarter million men. The JSDF plays no regional defense roles, and in fact rarely ventures outside the contiguous waters of Japan. With the most productive shipyards in the world and a merchant fleet that dwarfs our own, Japan has a minuscule, coastal defense navy whose entire tonnage is less than that of three American aircraft carriers, and whose principal combat ships are 48 small destroyers and 14 submarines.

The Japanese compete with us in markets throughout the world, moving their goods along trade routes which we protect with an overworked and beleaguered Navy. They rely totally on the United States for the protection of their Persian Gulf oil supplies, which provide 80 percent of their petroleum needs and only 7 percent of our own. They trade freely with the communist nations due to the calm which our presence provides: $10 billion in two-way trade with China last year, and a mind- boggling relationship with North Korea that has made Japan its principal free world trade partner, its "trade lifeline" with the non-communist world, even as we maintain 38,000 combat troops in South Korea, partially to ensure Japan's security from the advances of those same North Koreans.

Free from the cost of maintaining a military commensurate with its economic power, Japan has enjoyed a consistent and substantial bilateral trade surplus with the United States that drains our economy -- $18 billion last year alone -- and is investing heavily on the American mainland. The evidence is persuasive that Japan will grow stronger: its own government's Economic Council recently predicted that by the end of this century their per capita gross national product will have substantially topped ours, $21,510 to $17,600. And yet it suffers little of the economic drain from defense expenditures which has traditionally been the price a nation has had to pay in order to engage heavily in international trade.

Except in the narrowest sense of self-defense, our armed forces are the Japanese military, incurring all its international security obligations in addition to our own. Some 46,000 Americans are stationed on Japanese soil, more than in any foreign country except West Germany, and many of the 25,000 deployed personnel of the Seventh Fleet are often in nearby waters. Nine U.S. Navy ships are "permanently forward deployed" in Japanese ports. The 3rd Marine Division operates out of Okinawa, as does the Air Force's 313th Air Division.

In many cases, American and Japanese security burdens overlap. However, Japanese opinion, both government and public, seems to have been that in all cases they overlap, so that American defense of Japanese security interests is simply incidental to our own strategic responsibilities. For example, it is true that Japanese oil tankers are secure in their Persian Gulf journeys because of the presence of the American fleet, which has stabilized the region for reasons related to American security. What is not clear to the Japanese is that their Persian Gulf sources either would dry up or be suffered at the hands of the communist nations should the Americans cease providing this protection. Since that prospect is unthinkable from an American perspective, and since its results would signal a total realignment of world power, the cost to the United States is not regarded as a Japanese problem. In fact, the clearest public sentiment in Japan over at least the past decade has been toward a nonmilitary centrism, an equidistance from the United States, China and the Soviet Union.

The Soviet invasion of Afghanistan and its threats to Poland, coupled with the unrelenting growth of the Soviet Navy, have awakened the perceptions of many Japanese regarding Soviet intentions in the world. Nonetheless, the Japanese logic regarding such dangers is in effect to kill a potential enemy with kindness rather than to confront him militarily, to make him so economically dependent on Japanese goods and services that he will want to foster good relations.

A recent poll conducted by the Japanese newspaper Asahi Shimbun showed 70 percent of the country taking a negative stance against the very modest Japanese military buildup now being proposed by the ruling Liberal Democratic Party. Some of this negativism can be passed off as economic self-interest. The rest of it should be construed as genuine revulsion toward a militarism that caused 2 million Japanese to perish on the battlefield in World War II -- five times the combat deaths from a country half as large as the United States -- with the resulting destruction not only of the Japanese Empire but of much of the homeland itself. Either way, the point is clear: Japan now is secure, and has accomplished many of the economic aims for which it once went to war. Strengthening its military forces seems unnecessary and provocative to many Japanese.

Against such a backdrop, and in light of the Japanese government's tendency to seek harmony in its policies rather than indulging in the confrontation process so familiar to the United States political system, the recent 7.754 percent increase in the Japanese defense budget during a period of austerity, accompanied by the many official statements regarding Japan's moral debt to the United States military for its present economic well being, should be regarded as major steps toward a larger role by Japan in the defense of the Pacific region. Toward this end, defense experts from Japan and the United States have been meeting regularly for the past year in an effort to redefine mutual security obligations, focusing on roles and missions performed by the two countries.

Adjustments will not come easily. The Soviet Union has already criticized Japan's "militarization" during talks between the two countries. The Japanese Socialist Party, which is the major opposition party, is combining with other opposition parties to campaign not for military increases but for disarmament, and hopes to collect 10 million signatures during February to support its cause. Others will invoke the provision contained in Article IX of the Japanese Constitution in which the Japanese people forever renounce war, and state that "land, sea and air forces, as well as other war potential, will never be maintained."

The countries of eastern Asia, all of whom were occupied by Japan prior to 1943 and suffered under the cruel whip of Japanese militarism, will react with genuine fear (one clear example of the depth of these feelings comes from South Korea, whose people recently voted Japan the country they feared most, except for North Korea -- ahead even of the Soviets).

Such dissent is answerable. First, the Soviets and the opposition can be expected to react negatively. Second, the famous "no-war" provision of Japan's Constitution was foisted upon the country in more idealistic times, and was interpreted in 1959 by the Japanese Supreme Court to allow Japan the inherent right of self-defense. Additionally, as early as 1951, the Japanese stated in the preamble to the first mutual security treaty their expectation "that Japan will increasingly assume responsibility for its own defense against direct and indirect invasion." This language was adopted after U.S. negotiator John Foster Dulles had urged the Japanese to undertake an active regional defense role, and then accepted Japan's assertion that it was too spiritually and economically weak at that time to do so.

Finally, the other countries of Asia, all of whom deal economically with the Japanese and many of whom house Japanese industry, should concern themselves more with the present than the past. Forty years ago, when the Japanese dominated eastern Asia, the Soviet Union did not even have a Navy. Today its fleet outnumbers the United States fleet by 200 ships, and by 1990 it is expected to be operating at least five carrier-centered battle groups. The United States needs help, and Japan is capable of giving it.

What form that help should take, in the long run, is subject to legitimate debate. The options range from full militarization, on the one hand, to a flat payment by Japan for the U.S. protection of its commerce outside Japanese contiguous waters.

There already have been stirrings in the U.S. Congress, prompted by the trade imbalance between our two countries. Sen. Jesse Helms of North Carolina has called for renegotiation of the mutual security treaty, with Japan assuming new responsibilities. Rep. Clement Zablocki of Wisconsin has introduced a joint resolution which would require Japan to spend a full 1 percent of its GNP on defense, and is said to have the full interest of Sen. John Glenn of Ohio.

In a unique approach, Rep. Steven Neal of North Carolina recently introduced a "security tax" resolution, calling for Japan to pay the United States 2 percent of its GNP for the protection we provide it. Although the measure has attracted little attention among his colleagues, it has caused more than a dozen Japanese press and government officials to make their way to his office in the last three months, evidence of how closely the Japanese are following the American perspective on this issue.

But the greatest mistake Americans could make would be to attempt to attempt to publicly dictate terms to the Japanese, or to give the impression that we believe we have the right to control the internal policies of the Japanese government. The crushed, remonstrating dependency of 1946 has grown up and it has reassumed its role as a dominant force in Asia. It should be remembered that the Japanese government's cooperation on defense matters seems to stem more from a desire to demonstrate its good will as a responsible economic partner than it does from a truly perceived threat. The wrong sort of American pressure while its government is attempting to develop consensus among a citizenry leaning strongly toward centrism could boomerang badly, no matter how well intentioned our policy makers.

Now should it be forgotten that the very thought of large complements of Japanese soldiers bearing guns, piloting aircraft and commanding warships somehow rankles Americans, terrifies Asians and genuinely perturbs most Japanese themselves. It is a safe bet that the reappearance of Japanese combat forces of any scale on the terrain they so harshly controlled prior to 1945 would cause emotional repercussions that could unsettle Asia.

For these reasons, the task of American opinion makers and officials should not be to decide whether or under what conditions Japan should rearm, but rather to clarify to the Japanese what our own deficiencies are, and to pressure them to think creatively about complementary solutions.

For perhaps the first time, they seem to be convinced we are serious about their contribution to the regional security of Pacific Asia, and are devoting much energy to a solution.

They were smart enough to keep us in this situation for 30 years. Who knows? As the recent proposal to provide $10 billion in aid to this country suggests, Japan may now have the most innovative way to get us out of it.