WHY FOR GOD'S SAKE, Henry Kissinger, again? Are we really going to learn to reason together about Central America from the man both liberals and conservatives love to hate? Does Ronald Reagan really want to revive the architect of detente, whom Reagan himself attacked so harshly in 1976 and promised to fire if he became president?

Well, why not? It had to happen one of these days. Kissinger had been inching himself back toward the golden throne for years, forever advertising his availability and assiduously realigning his Weltanschauung to accord with that now currently fashionable in Washington. Recall, if you will, his remarkable performance at the Republican convention in 1980 when, having failed to assure his return to office via Gerald Ford, he did a neat reverse shuffle designed to persuade the Reaganites that he was really one of them. Not neat enough, as it turned out. Or at least not then.

But now, at last, he has done it. The president has tapped him to head the new bipartisan commission on Central America. This is only a foothold, to be sure. Reagan has consigned his earlier observations about Kissinger to the memory hole, Jesse Helms has been defied, and those who think that the definition of a bipartisan foreign policy is one that unites hawks of both parties have been heartened.

Now that Kissinger has received official unction we should not be surprised to see him, should there be a second Reagan administration, on top of the mountain once again in place of the hapless and eminently unnoticeable George Shultz. To say that we could do worse -- in fact to say that we currently are doing worse -- is not so much to honor Henry Kissinger as to comment on the earnest amateurism with which our foreign policy is currently being conducted.

Henry Kissinger was allowed to play again, after all the naughty things that Reagan had said about him, because the administration desperately needs someone to sell its Central American policy. Having failed to persuade the public that the Yanqui-backed contras now invading Nicaragua are really "freedom fighters," it has decided to wheel out the old war horse of the "international communist conspiracy."

It was this argument, you will recall, that previous administrations used to demonstrate that North Vietnam was really a puppet of China, which in turn was a puppet of Russia. So now, we are told, it is the Cubans (on behalf of the Russians) who pull the strings in Nicaragua in their plan to seize all of Central America and inundate us with wetbacks.

To make the beleagured Marxists in Nicaragua and the guerrillas in El Salvador a mortal threat to the survival of the American republic requires considerable sleight-of-hand. Who better to perform this task than a proven master of deceit? It is as though Reagan's advisers, having read Seymour Hersh's blow-by-blow account of Kissinger's machinations, were so impressed that they decided to go for the top-of-the-line model.

In a sense he is. Who better than Kissinger to explain why a peasant rebellion in a little country exploited for generations by its own oligarchy, with the benign cooperation of a succession of U.S. administrations, has to be forcibly repressed by Amerian arms and, if need be, American soldiers? The answer lies, of course, in Realpolitik, in demonstrating that the problem in Central America has nothing to do with oppression and privilege and exploitation, but is really about the global contest between the superpowers.

Nicaragua, like El Salvador, is what Lyndon Johnson used to call a "piss-ant country." Superpower managers don't like to admit that what makes them superpowers is controlling piss-ant countries. They need a more exalted name for it. They call it the global balance of power.

Here Henry Kissinger is on home turf. Nicaragua and El Salvador offer a chs ance to do what he failed to pull off in Vietnam, and would have liked to do in Angola if Congress had let him. The United States, in his view, has to show the Russians that it can be as ruthless with the little countries in its shadow as they are with their satellites. That is geopolitics.

"If we cannot manage Central America," he recently told an interviewer in Public Opinion magazine, "it will be impossible to convince threatened nations in the Persian Gulf and in other places that we know how to manage the global equilibrium."

In his view everything is a problem of management, and other countries merely pawns in the great game of world politics. Too bad for the Nicaraguans if their little revolution gets in the way of the efforts of Washington and Moscow to corral off their mutual turfs. "I don't see why we have to let a country go Marxist just because its people are irresponsible," he told the White House's 40 Committee in June, 1970, as he plotted against Allende's government in Chile.

The Russians got on well with Kissinger. Compared with the current situation, the early 1970s seem like a Soviet-American honeymoon, and we are in dire need of the stability he brought to our relationship with Moscow. That was his virtue. But his failing is that he sees everything through geopolitical spectacles. Nothing matters but the great powers, and to them everything matters.

No solution is too minor to meddle in. Everything is connected, and within a superpower's sphere of influence the role of little countries is to obey. That is the Soviet view, and it is also Henry Kissinger's. To a global manager, the world is divided into stars and bit players. The star has all the lines and controls the action; the bit players pour him drinks and feed him cues.

For Henry Kissinger, Latin America has always been a joke. Argentina, he once said contemptuously, is a dagger pointed at the heart of Antarctica. What makes Latin America important today is that he has turned it into a symbol, a place to reassert U.S. authority in an area that has become messy and unmanageable. There is an itch for action in official Washington, an eagerness to stand up and win one. Since the enemy in this case is a band of bedraggled peasants and compromised revolutionaries, the effort has to be dignified by raising it to the level of global geopolitics.

The administration knows that the public doesn't want to get involved in a war in Central America. But it can be made to care if the issue is magnified. The stakes must be exaggerated, to be made "clearer than truth," to use Dean Acheson's phrase in explaining how he sold the Soviet threat to Congress. Out of step with the mood of the country, but eager for a fight, the administration needs a gimmick that will sell. The people it has to sell are political moderates of both parties who don't like ganging up on little countries but will go along if they can be persuaded that it is in the interest of global equilibrium. This is geopolitics, and to sell it the administration has brought in Henry Kissinger.

His assigned task is not to find a new policy, but to justify the present one. It is an assignment in public relations. Kissinger is on probation with Reagan, rather like an assistant professor being scrutinized for possible tenure. Rather than challenge his superior, he will flatter and try to please. He will tell Reagan what he wants to hear and do what Reagan wants to do. That is the path to power and promotion. That is what he learned in service to Richard Nixon.

The rise, triumph, decline, and now rehabilitation of Kissinger is the stuff that sagas are made of. Name another secretary of state, except for Thomas Jefferson, who remained nearly as important outside of public office as in it. With no formal power base of his own he has been a media personality and, to some, an oracle. His show-biz notoriety, his corporate connections, his links to the glitterati and the mighty have enhanced his authority. Witness a chs the gaggle of Somebodies that gathered recently to fete his 60th birthday.

Kissinger undeniably has allure. He won his way into the foreign policy establishment by a combination of intelligence and sycophancy. Later he added charm and wit to broaden his constituency. But the key factor was the sheer allure of power, power that attracts by its mere existence, and magnifies in appeal by its exercise. With the rich it is the power of money that makes others seek their company and feel privileged by doing so. With show business personalities it is the reflected glory that comes from fame and instant recognition.

With Henry Kissinger, who has understood the principles of show business better than any other public official, it is the ruthless exercise of power in what is said to be a higher cause. If Kissinger were Attila the Hun he would still attract crowds, for everyone loves to see a monster. But he would not grace the most fashionable dinner parties. For that something more is needed: finesse, wit, and a justifying raison d'etat.

Thus it is Kissinger's dedication to Realpolitik, power in the service of itself and divorced from principle, that makes him for some so contemptible, for others so irresistible, and for all so inescapable. Yes, he has lied; yes, he has been a chief architect of policies that inflicted pain on the innocent and the helpless. Those offended by such behavior can usually be silenced by accusations of cowardice (consider what we have learned about the conversations in the Nixon White House) or, for purposes of public consumption, appeals to such higher principles as the global struggle for power.

The Reagan administration does not have different values than Henry Kissinger. It merely is incapable of expressing them so coherently or persuasively. This is why, finally, he had to be brought back, why the president who once castigated him as the evil perpetrator of detente now hails him as a "very distinguished American, virtually a legend in that field" of diplomacy.

That he is, and since we live in a time of legends and myths -- the legend of the now receding American Century and the myth of American moral infallibility -- how appropriate it is that Henry Kissinger, spruced up in the latest Reaganite coloring to accord with his new habitat, should be allowed back into the Citadel.

Yes, there is a lot of blood around him, the blood of Vietnamese, Cambodians, Bengalis, Chileans -- Angolans and Ethopians, too, if he had had his way. But then all those places, as he reportedly said of Latin America, are "outside of history." They are so troublesome -- because in themselves they matter so little; just like those who are sent off to fight in them.

The fact that Kissinger does not know, or particularly care, much about Latin America is almost irrelevant. He has been brought back into the government, if only temporarily so far, to make justifiable that which the zealots and novices of the Reagan administration have not been able to justify. His job is to persuade us all that, alas, it is, after all, a vital American interest to help overthrow the government in Nicaragua and silence dissent in El Salvador.

Henry Kissinger again, because no one else has been able to clothe brutality and unprincipled power in such flattering garments. No one else has shown such an ability to manipulate the levers of government, seduce the press, and overwhelm a Congress jealous of its prerogatives. Perhaps the secret of Henry Kissinger's remarkable success is that he remains totally outside the system even when formally within it. He is as contemptuous of Congress and the courts as he is of public opinion. They are instruments to be used or impediments to be circumvented.

Should we bemoan his return? Not, I think, if we want to restore a needed measure of professionalism to our diplomacy and to defuse the dangerous tension that has been allowed to develop between Washington and Moscow. Yes, if we think that our foreign policy should have some s connection with the values we profess.

But the choice will not be made on that basis. Kissinger is back in Washington today not because the nation lacks experienced diplomats, nor because he is more ruthless than those already in positions of authority. Rather it is because he can make a diplomatic extravaganza out of an operation that has been marked until now by amateurism and ideological zealotry.

Kissinger's special talent, after all, has always been to provide a compelling rationale for doing the unspeakable in service of the unnecessary. That is why he is needed now. Conspirator, bully, charmer and salesman, Henry Kissinger embodies the darker side of our worldly ambitions. There will always be a place for him.