The U.S. invaded Cambodia last May because a steady increase in American casualties before the invasion presented the Administration with a choice of invading Cambodia or withdrawing from Vietnam completely, Henry A. Kissinger '50 told a group of students led by Stanley H. Hoffmann, professor of Government-who visited him last month in the White House.

Kissinger, President Nixon's National Security Adviser, said that critics who asked why the Administration had not kept to its schedule of withdrawals at that time did not realize the serious implications of the rise in American battlefield deaths, according to one student who attended the meeting.

Off the Record

About 20 undergraduates and graduate students flew with Hoffmann to Washington to attend the meeting which was held strictly off the record at Kissinger's request. The session was held in the White House Situation Room, where President Nixon is briefed during crises. As Kissinger talked with the group, students could see a map of Cambodia on the wall.

"Royaume de Cambodge (Kingdom of Cambodia)" was the inscription on the map, but the words "Kingdom of" had been crossed off in pencil.

Tense Meeting

The student described the meeting as tense, adding that while most of the students seemed to relate to Kissinger as they would to a Harvard professor-deferentially and politely- "three or four" were more hostile, asking hostile questions about the Administration's Vietnam policy and Kissinger's role in shaping that policy.

At the beginning of the meeting, Kissinger told the group emphatically. "This meeting is off the record, which means that if anybody asks, it didn't take place."

Something to Hide

"One got the feeling that he had something to hide," the student said yesterday. "The recent U.S. air invasion of Cambodia has made clear the duplicity of his position. He claimed then that we were de-escalating with only 'ups and downs.' Now we see what the 'ups' are."

Shortly afterward, one member of the group called the U.S. policy of massive bombing raids in Vietnam, Laos, and Cambodia genocide.

"Go easy on words like genocide," Kissinger retorted. He then said that the Nixon administration has conducted a more restrained bombing policy than the Johnson administration. "It is not the policy of the United States to bomb people," he stated.

Complete Withdrawal

Kissinger then detailed his version of the Administration's policy in Indochina. He predicted that the U.S. would be able to withdraw from Vietnam completely by an unspecified, date, leaving the Saigon government to continue the war on its own.

When a member of the group asked what the Administration would do if the Saigon government were overthrown after the proposed withdrawal was completed, Kissinger replied that this would make no difference in the policy.

"It is not the policy of the United States to maintain a government in South Vietnam against the wishes of the people," he said. Pressed by members of the group who contended that the present government of South Vietnam is a military dictatorship maintained by American power, he repeated the phrase.

Kissinger expressed fears that a severe rightwing backlash could arise in the United States if U.S. troops were withdrawn too quickly and the present South Vietnamese government fell.

Toward the end of the interview, Kissinger said with a trace of bitterness, "I would like to come to Cambridge to discuss this with you further, but there are some of your number who might seek to prevent me."

Unfriendly Questions

Although Kissinger was amiable for the most part, he appeared annoyed at times by the unfriendly questions. "If you know all the answers, why do you ask me questions?" he replied to one student who had asked a long-and hostile-question.

At another point, when a member of the group asked why the Administration was "manipulating public opinion" on the question of American prisoners of war held in North Vietnam, Kissinger glanced at his watch and announced that he was due at a meeting and could not stay to answer more questions.

However, before ending the session, he answered two questions about the U. S.- Soviet Strategic Arms Limitation Talks.

He then left the room, which was guarded by White House guards in gaudy uniforms.

"Before the meeting, a lot of people had been talking about putting him on the spot by asking really good questions," one student said. "But, once it started, a lot of us felt as if we were talking to a professor. Some were unwilling to ask unpleasant questions or to interrupt him and try to pin him down. As a result, a lot of people asked very easy questions-questions that made it very easy for him to give long, meaningless answers. And a lot of the really serious questions were asked in a deferential way that made it really easy for him to get off the hook.

"By the end of the meeting I was convinced that he was deceiving himself and lying to us," the student said. "The Nixon policy does not mean an end to the war against the people of Southeast Asia."