ON FRIDAY, MARCH 6, Leigh S. Ratiner, a Washington attorney, went to see George H. Aldrich. Aldrich acting head of the U.S. Law of the Sea delegation, was in New York. The 10th six-week session of the conference was about to begin at the United Nations. Ratiner, a former U.S. negotiator at the 1975-76 conference, wanted help getting access to other delegations -- he had a contract from the Commerce Department to survey foreign ocean mining laws. Aldrich promised his people would help.

Ratiner then announced that James L. Malone, an incoming assistant secretary of state, wanted him on the U.S. delegation as his personal representative. According to informed sources close to the delegation, Aldrich told him this was impossible: Ratiner did not have a current security clearance.

The next day, Deputy Secretary of State William P. Clark dismissed Aldrich and most of his senior staff. Malone became the new chief and Ratiner a member of the delegation. Malone, assistant secretary for oceans and international environmental and scientific affairs, has limited background in Law of the Sea issues. Ratiner was appointed as an "expert" to advise Malone during at least the first couple of weeks of the conference session.

The firings stunned the State Department. They amazed the delegates from 158 countries who were assembling in New York, where the conference was to open that Monday. (One U.S. delegate, John Temple Swing, learned of his dismissal while reading a newspaper as he made his way to the conference by subway on Monday morning.)

Five days before, on March 2, the State Department issued a terse nine-line press release on Clark's orders. The secretary of state had "instructed our representative to the U.N. Law of the Sea conference to seek to ensure that the negotiations do not end at the present session of the conference, pending policy review by the United States Government." No U.S. ally, much less any other foreign country, was informed before the public announcement. The American decision flabbergasted them. All had expected this session to be the last lap in a diplomatic marathon that the starter's gun set off seven long years ago.

A new administration clearly has the right to review inherited policy. It clearly has the right to appoint its own people to key positions. Yet the way the changes were made has deeply hurt America's credibility in the world and raised troubling questions about the Reagan administration's conduct of diplomacy.

Other delegations are very disturbed by the appointment of Ratiner, a man with wide contacts but deeply suspect to many at the conference, and indeed to some on the U.S. team.

As soon as he came on board, Ratiner began to promote Christopher W. Pinto of Sri Lanka for conference president, though officially the United States had no candidate. The former president, H. Shirley Amerasinghe, also a Sri Lankan, died last December. Ratiner is a close friend of Pinto and seems to have convinced Malone that the United States could control the conference through him, according to informed sources. However, Ratiner was set back on March 13 when the conference instead selected T.T.B. (Tommy) Koh of Singapore as president.

Ratiner headed the Interior Department's Ocean Mining Administration in 1975-76. As such, he was chief U.S. negotiator for deep seabed mineral issues at the law of the Sea conference. In early 1977 he left the government to become a partner in the high-powered law firm of Dickstein, Shapiro and Morin. According to his resume, he has since been "counsel and adviser to several major corporations with economic interests in international resource negotiations, including the U.N. Law of the Sea conference."

One corporate client was Kennecott Copper, leader of an ocean mining consortium. Ratiner resigned from the Interior Department on Jan. 24, 1977. On Jan. 25 he resigned as a lobbyist for Kennecott, through the corporation dispensed with his services in 1979. In April 1977 he testified on ocean mining before a House committee without declaring his link to Kennecott, a company particularly vocal in its opposition to the draft Law of the Sea treaty.

Ratiner was widely rumored to have had something to do with surprising and mysterious revisions to a compromise treaty text during the sixth session of the conference in July 1977. The revisions, drawn up by a small group of Third World negotiators including Pinto, made that draft impossible for the United States to accept.

Last year Ratiner played an important role in forcing U.S. reconsideration of the proposed U.N. Moon Treaty. This treaty, which awaits ratification, declares the resources of the moon and outer space to be the "common heritage of mankind." "Common heritage" is a term from the ocean law negotiations. The U.N. General Assembly adopted it as a description of the seabed's resources in 1970, with the United States voting in favor.

Ratiner is close to Rep. John B. Breaux (D-La.), a leading critic of both the Moon Treaty and the Law of the Sea conference. Breaux and 13 House colleagues wrote to Reagan last Dec. 10 to urge a review of the draft Law of the Sea Treaty. They were concerned that this spring's negotiation "may produce a fundamentally unacceptable result.

Theodore Kronmuller, an aide to Breaux, drafted the letter. Kronmuller wrote a dissertation at Cambridge University that concluded it is lawful for companies to mine the seabed even without a Law of the Sea treaty. Kronmuller is today a leading candidate to become a deputy assistant secretary of state under Malone.

The influence of Ratiner, Breaux and Kronmuller on Malone and the administration's abrupt actions have cast a pall over the Law of the Sea conference. Many delegations now believe the United States is preparing to withdraw from the negotiations. Foreign nations wonder if they can trust Washington.

Trust has been an essential ingredient in bringing 158 nations so far over the last seven years. "The only way the conference has been able to progress as it has is on the basis of trust and confidence among those negotiating," says Lee Kimball, a consultant to the United Methodist Law of the Sea Project and a longtime observer of the conference. "It's incredible that the U.S. has been able to stymie the momentum of the conference when every other nation, including our European allies, wanted to conclude it."

The 320-paragraph draft treaty they expected to complete this April is essentially a compromise. It sets international boundaries: 12 miles for territorial waters and 200 for "exclusive economic zones" (EEZs). It guarantees navigation and aircraft overflight rights on the high seas, through the EEZs and through straits.

The Joint Chiefs of Staff are eager to have these navigation rights. With them, the Navy can steam uncontested through strategic straits like Gibraltar and Hormuz. With them, its submarines can remain underwater as they pass through coastal seas that other nations are increasingly claiming as sovereign. "Creeping juridsiction" -- the unilateral extension of territorial waters -- has become a serious problem in the last 20 years. The treaty would lay it to rest, enhancing U.S. national security.

As a quid pro quo for granting these navigation rights the treaty gives the Third World a share in the wealth of the seabed. Over 1.5 trillion tons of black, potato-shaped nodules, rich in nickel, copper, manganese and cobalt, lie on the ocean floor. Nobody knows how they got there. Most are in the Pacific, at depths of 12,000 feet and below.

"The Enterprise," not a spaceship but a new U.N. agency, would control development of the nodules and itself operate some mines, distributing their profits to the developing nations. The idea behind this is that as the nodules belong to no one, as they are mankind's "common heritage," their exploitation should benefit the poor countries of the world.

At the same time, the draft treaty gives firm title to ocean mines operated by commercial consortia from the industrialized countries. Four consortia exist at present, each headed by an American corporation: Lockheed, Kennecott, U.S. Steel and International Nickel.

The key to the mining arrangements is a parallel system: Each site mined by a private consortium will be matched with one mined by The Enterprise. But The Enterprise will need initial capital and knowhow. Only the private consortia have the technology to mine the seabed. So the draft calls for the United States and other industrialized countries to provide startup funds and to transfer the necessary technology to The Enterprise.

The treaty also sets production limits on seabed mining. These restrictions, which the United States opposed, were added at the insistence of today's metal producers, led by Canada with its huge nickel deposits, who want to protect their domestic mining industries.

There are many other provisions in the draft treaty. It authorizes oil and gas development on the continental shelf, regulates fisheries, protects the marine environment, clarifies research rights for the industrialized countries and a share in seabed mining for the Third World.

Henry Kissinger set the basic deal in 1976. The Republican secretary of state told the U.N. that the United States would finance The Enterprise and make sure it got deep sea mining technology. The Carter administration appointed Elliot L. Richardson, a prominent Republican, as its chief negotiator. Aldrich, a career civil servant, became acting head of the delegation when Richardson resigned last year after almost four years on the job.

All the permanent heads of the U.S. delegation have been Republicans. Kimball pointed this out last Dec. 1 in a letter to the Reagan transition team. The conference, she wrote, has been "a negotiation entered into by a Republican administration, conducted throughout by Republican leaders and whose major avenues of compromise were determined by Republican policy experts and put forward by Republican spokesmen."

Yet it is a Republican administration that has deliberately capsized U.S. policy. How did this happen?

Malone's reliance on Ratiner is one recent factor. It is not the first time that the ambitious Malone, who was general counsel of the Arms Control and Disarmament Agency (ACDA) during 1973-76, has made a controversial appointment.

Indeed, his own job has raised questions. Sen. John Glenn (D-Ohio) held up his Senate confirmation, citing a possible conflict of interest between Malone's representation of Japanese and Taiwanese power companies as a lawyer during the Carter years and his new official responsibilities, which include overseeing nuclear nonproliferation policy.

While head of Reagan's transition team for ACDA, Malone hired an intelligence analyst named David S. Sullivan. The CAI forced Sullivan to resign in 1978 after he admitted breaching the agency's security rules. He had shown highly classified material dealing with Soviet missiles to Richard Perle, then an aide to Sen. Henry M. Jackson (D.-Wash.). Yet during the transition, Malone authorized Sullivan's access to information of the very type he had passed on to Perle in 1978. Adm. Stansfield Turner, outgoing CIA chief, was furious, and shock waves rippled through the national security community. Sullivan remains at ACDA.

Still, the change in U.S. policy has deeper origins than Malone's judgment of individuals. The mining industry has long worried about some draft treaty provisions. Thus, before the dramatic events of early March, U.S. policy was to tighten up the mining clauses. In particular, the delegation sought to protect mining operations started after the conference concludes but before the treaty enters into effect.

It is important to note, however, that the majority of the mining consortia only wanted the terms of the treaty changed. Most still want a treaty rather than no treaty. Without one, they would not have secure title to their ocean mines. And no bank is likely to lend them investment funds for 30-year projects like deep sea mines unless there is guaranteed title.

Also behind the changed American policy is growing apprehension in Reaganz's Defense and Interior departments that excessive concern with one key aspect of national security -- navigation rights -- has deflected attention from the equally important question of the supply of essential raw materials (a question given new emphasis by the March 13 announcement of renewed purchasing for U.S. strategic mineral stockpiles for the first time in 20 years.)

The Navy, for example, needs to be able to sail through straits without surfacing its submarines; it also needs special steel alloys for their hulls. The alloys require minerals like cobalt which are today supplied by potentially unstable places like southern Africa but tomorrow could come from the seabed. Yet, this argument goes on, the Third World might control the critical ocean minerals through The Enterprise, and this denial of assured access could jeopardize U.S. security.

This view does not go unchallenged. It is not clear, its critics contend, that mineral supplies from, say, southern Africa would be cut off even if that simmering cauldron does boil over. Gulf Oil has continued to produce oil in Angola throughout its civil war and with the blessing of its Marxist government. Nor is there any reason to think that ocean mines are any more secure than those on land. If it wanted, an unfriendly country -- or a terrorist group -- could surley disrupt production at a 12,000-foot-deep facility in the middle of the Pacific.

The Reagan administration, with its strong support of free enterprise, has also lent a sympathetic ear to those who complain that the United States has let the Group of 77 (the developing countries) get away with too mcuh in various multilateral negotiations, who contend that America has been too soft.

Among this group is Sen. Jackson, who approves the decision to review the treaty. He told the Senate on March 10: "One of the main forces in the Law of the Sea negotiations is the Third World drive toward the establishment of the New International Economic Order. This concept . . . is calculated to make a fundamental redistribution of global wealth and power from the nations of the industrialized North to the countries of the less developed South." The Enterprise, the mandatory transfer of mining technology, and the controls on seabed mineral production are all seen by these critics as part of a Soviet-inspired model of central planning.

Another alleged fault the Reagan transition teams identified in the Law of the Sea delegation was that it had become too independant. Its members were thought to have spent so many years on the conference that they had acquired a vested interest in obtaining a final treaty. This, it was felt, had clouded their judgement of America's overall national interest. The delegation had to be made more responsive to its political masters.

Thus the administration considered replacing Aldrich when it took office, an action long favored by some of the mining companies. Taking soundings on Capitol Hill, the administration was told that Aldrich himself was not the problem. Rather, the delegation's instructions were too loose and too much written by Aldrich's own office, known in State Department acronymese as D/LOS. So Assistant Secretary Malone tried to have D/Los, an independant office that reported directly to the deputy secretary, placed under his immediate control.

Even so, the administration did not really focus on the Law of the Sea conference until the March 2 meeting of a senior interagency group, held at deputy decretary level, chaired by Clark and orchestrated by Malone, according to State Department sources.

The meeting's outcome was never in doubt: It would opt for delaying a final treaty beyond the current conference session, pending a review. Yet the vehemence of those who opposed the treaty came as a surprise. So did the strong argument of the deputy secretary of defense, C. Fred Ikle, head of ACDA when Malone was general counsel, that the mining clauses did affect national security. The representative of the Joint Chiefs of staff, however, held to the traditional Defense Department view that navigation rights are the principal U.S. strategic concern and so the treaty should be concluded quickly.

A final surprise was Clark's decision to announce the review at once. The U.S. delegation had no time to warn its allies, or indeed key delegates from unfriendly countries. Clark had become annoyed at leaks from other interagency meetings. So he preempted a leak from this one. Apparently he had no intention of upsetting other countries. Yet that was the result.

The U.S. delegation, in New York later in the week for prepratory meetings, was in a different position. The press announcement "put me on the spot with other countries," said one senior member. The wholesale firings over the weekend added to foreign dismay at the United States.

The allies are upset at the lack of prior notification. Some have registered pointedly about the value of past U.S. assurances. The administration is no longer prepared to assure other countries that it remains committed to the parallel mining system, to the principle of "common heritage," or indeed to having a treaty at all.

There is now a real possibility that the treaty -- a compromise, as we have seen -- will collapse. The Group of 77 is furious because many of its members genuinely believe they have made important concessions over navigation rights. If the United States decided as a result of the review that it will reopen the mining sections of the treaty, the Third World may very well reopen navigation and overflight rights.

Did this have to happen? If the administration had gotten its act together and decided what it wanted, it could probably have avoided the mess it has created. With better planning -- with forethought -- the U.S. could have preserved the diplomatic capital amassed over seven long years only to be thrown away in five short days.

"I had the impression," says Rep. Berkley Bedell (D-Iowa), a congressional adviser to the delegation who was in New York for the first week of the conference and spoke to a number of other delegations, "that if the administration had gone up to the session and said, 'Look, we really want to see a treaty and to get it ratified but we'll have trouble with the Senate unless there are some changes, then other nations would have been receptive and would have tried to see if they could do it."

Instead, there is now review. The administration will promise nothing except that it is across-the-board and will be completed as rapidly as possible -- "certainly this calendar year," Malone told the Senate Foreign Relations Committee on Monday. As the review proceeds, this Republican administration will do well to remember a prominent Republican's testimony before the House Foreign Affairs Committee on Dec. 19, 1979.

"It must be recognized that any treaty that has any prospect of widespread acceptance will have costs as well as benefits," said Elliot Richardson. "Its measures is not whether it is better than the law as we would write it if we could. The measure is whether it is better than the situations most likely to evolve without it."