The Johnson administration planned for major American military action against North Vietnam nearly five months before the 1964 Tonkin Gulf incident, according to secret government documents made public yesterday by the New York Times.

These plans were made, the documents, show, at a time when the United States already was directing clandestine sabotage operations in the North.

Two months before the attack on two American destroyers in the Gulf of Tonkin on Aug. 2 and 4, 1964, the administration sent a Canadian diplomat, J. Blair Seaborn, on a secret mission to Hanoi where he is quoted as telling Premier Pham Van Dong that “in the event of escalation (of the war) the greatest devastation would result for the D.R.V. (North Vietnam) itself.”

It was the Tonkin incident - called totally unprovoked by the administration - which led Congress on Aug. 7, 1964 to pass a resolution declaring that the United States was “prepares, as the President directs, to take all necessary steps, including the use of armed force,” to assist South Vietnam. It was on this resolution that President Johnson subsequently leaned heavily to widen the war.

The documents are part of a multi-volumed collection of records and comments assembled under the direction of then Secretary of Defense Robert S. McNamara. The bulk of the documents disclosed this far by the Times are of military origin but include some White House and State Department papers that reached the Pentagon. Other documents were only alluded to or quoted from in the newspaper’s story.

A National Security Action Memorandum of March 17, 1964, presumably the result of a presidential decision, set out both the administration’s political aims and the basis for its military planning. A cable sent three days later by the President to Henry Cabot Lodge, then the American ambassador in Saigon illuminates his intentions.

The memorandum says that “we seek an independent non-Communist South Vietnam” but “do not require that it serve as a Western base or as a member of a Western alliance. South Vietnam must be free, however, to accept outside assistance as required to maintain its security.”

Repeating language from a McNamara memorandum of March 16 to the President (language in part drawn in turn from a memorandum to McNamara on Jan. 22 from the chairman of the Joint Chiefs of Staff, Gen. Maxwell D. Taylor) the National Security Council document reflects the prevailing belief in what President Eisenhower had called the “domino effect” of the loss of South Vietnam.

Unless the objective is achieved in South Vietnam, it says, “almost all of Southeast Asia will probably fall under Communist dominance” or accommodate to Communism. The Philippines, it was judged, “would become shaky” and “the threat to India on the west, Australia and New Zealand to the South, and Taiwan, Korea, and Japan to the north would be greatly increased.

The policy decision then was to “prepare immediately to be in a position on 72 hours’ notice to initiate the full range of Laotian and Cambodian ‘border control actions’” as well as “the ‘retaliatory actions’ against North Vietnam and to be in a position on 30 days’ notice to initiate the program of ‘graduated overt military pressure’ against North Vietnam . . . .”

The President’s cable to Lodge says that “our planning for action against the North is on a contingency basis” on the grounds that “overt military action” then was “premature.” Mr. Johnson offered as one reason that statement that “we expect a showdown between the Chinese and Soviet Communist parties and action against the North will be more practicable after than before a showdown.”

The President also told Lodge that part of his job then was “knocking down the idea of neutralization” of Vietnam, an idea advanced by then French President Charles deGaulle, “wherever it rears its ugly head and on this point I think that nothing is more important than to stop neutralist talk wherever we can by whatever means we can.”

The resulting contingency planning is shown in several documents. But other documents also show that as early as Dec. 21, 1963, a memorandum from McNamara to President Johnson referred to “plans for covert action into North Vietnam” that “present a wide variety of sabotage and psychological operations” that should “provide maximum pressure with minimum risk.”

This clandestine program became “Operation Plan 34-A,” launched on Feb. 1, 1964. It was described in a National Security memorandum the next month as “a modest ‘covert” program operated by South Vietnamese (and a few Chinese Nationalist) - a program so limited that it is unlikely to have any significant effect . . . .”

One source yesterday said, in retrospect, that these covert operations were in fact “very modest - and highly unsuccessful.” But they came to have profound significance in the Tonkin Gulf incident. McNamara, even in 1968 testimony reexamining the 1964 affair, professed to know little about the plan 34-A operations. He told Senate Foreign Relations Committee Chairman J. W. Fulbright (D-Ark.) that they were carried out by South Vietnamese against the North, “utilizing to some degree U.S. equipment.”

“I can’t describe the exact organization,” McNamara told Fulbright, “although I will be happy to try to obtain the information for you.”

It was charged by then Sen. Wayne Morse (D-Ore.) that the South Vietnamese attacks on North Vietnamese forces in the Gulf of Tonkin caused the North Vietnamese to fire upon U.S. destroyers Maddox and C. Turner Joy. McNamara, in 1968, told the Senate committee, however, that it was “monstrous” to insinuate that the United States “induced the incident” as an “excuse” to take retaliatory action. The retaliatory action was the opening rounds of U.S. bombing attacks upon North Vietnam.

According to the information disclosed by the Times, the Plan 34-A operations against the North during 1964 ranged from U-2 spy plane flights to parachuting sabotage and psychological warfare teams into the North Vietnamese citizens, sea-launched commando raids on rail and highway bridges and bombardment of coastal installations by PT boats.

These attacks were described as being under the Saigon control of Gen. Paul D. Harkins, then chief of the U.S. military assistance command, with joint planning by the South Vietnamese who carried out the operations themselves or with “hired personnel.”

Even before these covert operations began, however, the U.S. Joint Chiefs of Staff were reported recommending “increasingly bolder actions” including “aerial bombing of key North Vietnamese targets” and use of “United States forces as necessary in direct actions against North Vietnam.”

After the August, 1964, Gulf of Tonkin breakthrough to more open U.S. involvement in the fighting, the published documentation shows recommendations for considerably expanded covert operations against the North.

A memorandum prepared for Assistant Secretary of State William P. Bundy shows that part of the clandestine operations against the North were suspended immediately “after the first Tonkin Gulf incident” on Aug. 2, 1964, but that “successful maritime and airborne operations” were carried out in October.

The documents discuss clandestine operations carried out not only from South Vietnam but from Laos, against North Vietnam and against enemy-held areas of Laos. One document states that “earlier in the year (1964) several eight-man reconnaissance teams were parachuted into Laos as part of Operations Leaping Lena.” But the grim result reported was: “All of these teams were located by the enemy and only four survivors returned to RVN (South Vietnam).”

Such covert actions, however, were only a fragment of larger-scale U.S. involvement in the war which was contemplated in great detail before the Gulf of Tonkin incident.

From the March 17 presidential decisions there flowed planning of many kinds. There was a Saigon strategy meeting on April 19 and 20 that included Secretary of State Dean Rusk; Assistant Secretary William P. Bundy, who appears from the evidence to have been the chief non-military planner; Gen. Earle G. Wheeler, now chairman of the joint chiefs, and Lodge.

On April 30 Rusk flew to Ottawa to arrange for Seaborn, about to become Canada’s new man on the International Control Commission to carry a message to Hanoi in June. It was a carrot-and-stick message with hints of economic aid paired with the threat of “devastation.”

This was a 16-point plan for “D-Day,” referring to the date to be chosen for launching air attacks against North Vietnam. The proposed scenario ranged from “stall off any conference until “D-Day” through a proposed presidential speech calling for a joint congressional resolution authorizing action against North Vietnam.

The action proposed, starting on “D-Day,” range from mining North Vietnam’s ports to striking its bridges, military barracks, airfields, industries and other facilities first by U.S. aircraft. Simultaneously, on “D-Day,” it was proposed that the United States call for a conference on Vietnam and announce the purpose was “not to overthrow the North Vietnam regime nor to destroy the country, but to stop D.R.V.-directed efforts in the South.”

But military action was not to begin until favorable action on the resolution which Bundy drafted on May 25. That day and the day before, however, the National Security Council executive committee, the Times account said, recommended to the President only some of the steps, and it called for sending the Canadian to Hanoi with his warning.

A Bundy memorandum written on the second day of the committee’s discussion says in part:

“Ambassador Lodge questioned the need for it (the congressional resolution) if we were to confine our actions to ‘tit-for-tat’ air attacks against North Vietnam. However, Secretaries McNamara and Rusk and CIA Director (John) McCone all argued in favor of the resolution. In support, McNamara pointed to the need to guarantee South Vietnam’s defense against retaliatory air attacks and against more drastic reaction by North Vietnam and Communist China. He added that it might be necessary, as the action unfolded . . . to deploy as many as seven divisions . . . .”

There followed next large preparatory military deployments, word of which in some cases was deliberately leaked in hopes it would have a deterrent effect on Hanoi. Aid too, was stepped up for the clandestine military operation in Laos against the Communists.

Quotations from a June query by Mr. Johnson to the CIA indicate that the President still was uncertain about enlarging military operations. He asked: “Would the rest of Southeast Asia necessarily fall if Laos and South Vietnam came under North Vietnamese control?”

The CIA reply was a challenge to the domino theory, saying that except for Cambodia “it is likely that no nation in the area would quickly succumb to Communism,” but that the loss “would be profoundly damaging the the U.S. position in the the Far East” and would raise Chinese prestige at the expense of the Soviet Union.

Summer of 1964 was national convention time for the two political parties in the United States. There is nothing in any of the documents that have been disclosed to indicate that President Johnson was swayed one way or the other by the coming election campaign.

However, the Tonkin Gulf incident changed the whole course of the war. Most of what is described by the Times about that incident already has been disclosed, in substance if not all in detail.

Once Congress passed the resolution, both planning and action quickened in pace. The United States immediately struck by air at North Vietnam in retaliation and on Aug. 10 Seaborn was sent back to see Premier Dong. Seaborn was told to say that if the North persisted in “its present course” it “can expect to continue to suffer the consequences.” This message, like many others referred to, was drafted by one of McNamara’s close aides, John t. McNaughton.

Hanoi’s response, according to the Times’ account, was that “Pham Van Dong showed himself utterly unintimidated and calmly resolved to pursue the course under which the D.R.V. was embarked to what he confidently expected would be its successful conclusion.”

The speed with which Johnson administration’s pre-planning in the Vietnamese war enabled it to move into action after the Gulf of Tonkin affair is illustrated by the documents.

Excerpts from a memorandum attributed to William Bundy, dated Aug. 11, 1964, discussed “courses of actions the U.S. might pursue, commencing in about two weeks, assuming that the Communist side does not react further” to “events of last week.”

This analysis stressed that “morale and momentum” in South Vietnam “must be maintained” and added, in part:

“We must continue to oppose any Vietnam conference, and must play the prospect of a Laos conference very carefully” at the outset.

A phase of “limited pressures” on Communist forces was proposed from “September through December,” to be succeeded by “more serious pressures (January 1965 and following)” all “foreshadowing systematic military action against” the North.

A memorandum dated a day later, Aug. 10, approved the Gulf Tonkin from Ambassador Maxwell D. Taylor in Saigon, estimated that the Saigon government then in power “has a 50-50 chance of lasting out the year.”

At that point, the public position of the United States was that it was only retaliating for attacks against its own forces. But the documents show that U.S. military planners were contemplating - and urging - escalating military action.

Only excerpts of some of these documents were published by the Times. Other sources cautioned yesterday that this published documentation is an incomplete record and that many recommendations made were never implemented by White House decisions.

Excerpts from an Aug. 17, 1964, cablegram from Adm. U.S. Grant Sharp, then U.S. commander-in-chief of Pacific forces, shows Sharp stating that:

“. . . We have already taken the large initial step of putting U.S. combat forces into Southeast Asia. We must maintain this posture: to reduce it would have a dangerous impact on the morale and will of all people in Southeast Asia. And we must face up to the fact that these forces will be deployed for some time . . .

“A conference to include Vietnam, before we have overcome the insurgency, would lose U.S. our allies in Southeast Asia and represent a defeat for the United States & we must recognize that immediate action is required to protect our present heavy military investment in R.V.N.”

Sharp said that U.S. command in Saigon reported that “We must rely on U.S. troops” and he had requested initial forces. Sharp asked for “consideration” of “creating a U.S. base” in South Vietnam.

Another document, described as a memorandum dated Aug. 27, 1964, from Air Force Maj. Gen. Rollen H. Anthis to the Joint Chiefs of Staff and others, lists recommendations from the U.S. command in Saigon for covert military operations in September.

It includes such proposals as “destruction of section of Hanoi-Vinh railroad by infiltrated demolition team supported by two VN (Vietnamese) marine squads,” and “four missions to airdrop new psy-ops sabotage teams” during the “light-of-moon period 16-28 September.”

Further plans for clandestine operations against North Vietnam were discussed in a Nov. 7, 1964, memorandum for Assistant Secretary of State Bundy, reportedly drafted by Deputy Assistant Secretary of State Marshall Green.

This document says that they United States, together with the government of Laos and South Vietnam, was “involved in a number of operations & designed to warn and harass North Vietnam” and reduce its capacity to reinforce Communist units in Laos and South Vietnam.

According to a commentary in the account published by the Times, the Pentagon study shows that the August, 1964, air reprisal strikes against North Vietnam” and reduce that “an important threshold in the war” had been crossed with “virtually no domestic criticism.”