On a wall in the lobby of the U.S. Mission to the United Nations are listed, in silvery metal type, the names of the 16 persons, beginning with Edward Stettinius, who have served as head of the mission since the United Nations was born in 1945. The two leaders in length of service are Henry Cabot Lodge and Adlai Stevenson, both of whom served before the transformation of the United Nations, in the mid- '60s, into a radical, lawless, anti- American institution dominated by a Third World rabble.

The person third in length of service is the current ambassador. Nowhere is "the Reagan difference" in public life more dramatically illustrated than in the sequence of the last three names on the list on the wall:

Andrew Young

Donald McHenry

Jeane Kirkpatrick

Because of her, the United Nations, although still dreadful, has changed for the better. The drumbeat of anti-Israel diatribes has abated somewhat. The United States has taken the fun out of it merely by answering back. Today a market economy is a social arrangement that is at least discussable as a model for developing countries. Furthermore, there has been established, almost in spite of the State Department, the principle that ideas have consequences. That is, linkage is alive and well where Kirkpatrick has a say. Hostile words and deeds in multilateral settings often bring hostile U.S. actions in bilateral relations with the offending countries.

But these achievements have taken a toll on the achiever. What she has done could only have been done by someone who must stiffen her sinews and summon her blood just to go to work day after day at such a dreary place. (When I recently made an appointment to meet her at her office, I asked the address. She paused, thinking, then said that such has been her reluctance to identify with the place, she has never learned the address.)

Her duties involve physical as well as mental wear-and-tear. There is the oppressive need to socialize with and acknowledge the pretenses of representatives of 150 or so nations, demi- nations, semi-nations and political conspiracies masquerading as nations. Furthermore, in the politics of policy- making at the highest levels of the executive branch, proximity to the president is, if not everything, an awful lot. To maintain that proximity, Kirkpatrick usually makes at least three trips to Washington each week.

But what is she, the one indispensable person in government, to do now? Staying at the United Nations would be an extension of unpleasantness in an office she has outgrown, and she has recently announced her "intention" and "desire" to leave.

She could become what Ed Meese, the next attorney general, has been -- counselor to the president. That would certainly solve the proximity problem. An office in the West Wing of the White House gives the occupant an enormous advantage in Washington's more-proximate-than-thou competition.

But proximity is only a necessary, not a sufficient, condition for effectiveness. Proximity without a responsibility avails little. A critic without portfolio is an obnoxious bystander.

A recurring theme in Churchill's six- volume history of the Second World War is the inherent weakness and frustrations of any office that does not involve direct responsibility for the operations of an agency. Unless you have a right to participate in the flow of the papers that make up the policy-making process, you are reduced, in Churchill's words, to "an exalted brooding over the work of others." Or, as an aphorist (H. Kissinger) puts the point, "Never take a job that has no 'in' box."

Two jobs commensurate with Kirkpatrick's capacities -- secretary of state and national security adviser to the president -- are occupied, for now. No friend would wish for her an unnecessary minute in the U.N. swamp. But no friend of the nation can equably contemplate her departure from high policy councils, for reasons I shall enumerate in my next column.

When at last she lays down the U.N. burden, there are excellent persons to replace her -- Leonard Garment, Frank Shakespeare, Max Kampelman. (Kampelman, like Kirkpatrick, is a Scoop Jackson Democrat.) On the other hand, she may find her burden more bearable when she hears the rumors that Sen. Charles Percy, just defeated, is a candidate for her job. For the foreseeable future, she should stay where she is, comforted by the fact that not much of the future is foreseeable.

It has been well said that "talent is a long patience." That is, talent is not a gift; it is the result of slow, disciplined refinement of gifts. Kirkpatrick's talents are manifold and manifest. She unites thought and action, theory and practice, better than anyone in government in this generation. She surely knows that patience, too, is a talent. It is central to politics, where circumstances must ripen.