A group of 100 moderate students are drafting a second letter to President Johnson to request a meeting to discuss their doubts about the administration's Vietnam policy.

The students, including Gregory B. Craig '67, former president of the Harvard Undergraduate Council, were completing the final version of the letter late yesterday.

Their first letter, which was sent to the President in December, resulted in a meeting with Secretary of State Dean Rusk in late January.

The new letter explains that Rusk failed to resolve their doubts then, and contends that recent government actions have caused student "disaffection" to increase. The letter will warn what will happen if the Administration refuses to clarify its present policy.

"To plunge deeper into an undeclared war," a tentative version of the letter says, "about whose purpose many are in doubt could produce an increased spirit of non-cooperation among those who have to bear its brunt. Such a reaction cannot be averted much longer by continuing the series of optimistic military forecasts that have undermined the reputations for foresight of high American officials over the past several years..."

"We cannot state too forcefully," the letter continues, "our conviction that any long range widening of the war risks domestic responses that could embarrass the government. Because we are disturbed by the prospect of widening non-cooperation at home, we are convinced that it is essential that the government take steps to indicate the good faith of its desire to negotiate."

Emphasizing that the steps must be "tangible and unequivocal," the students suggest acceptance of U.N. Secretary General U Thant's proposals as the "most effective way" to demonstrate good faith.

But the letter points out that stopping U.S. bombing and recognizing the National Liberation Front, as U Thant suggested, would not necessarily remove the obstacles to negotiations. "What we mean," explained Craig, "is that stopping the bombing won't be enough, if we continue to mine rivers at the same time."

The group states its concern over "what appears to be a conflict between our objectives of a negotiated settlement and other statements of government officials."

Citing Vice President Hubert Humphrey's statement that Vietcong political participation in Vietnam would be like "letting a fox into a chicken coop," the group asks how the Administration can expect the other side to come to the conference table without guaranteeing them a "meaningful political role."

The first version of the letter was drafted several weeks ago, but its release was postponed until after Senator Robert Kennedy's recent speech calling for a halt in U.S. bombing.

"When we heard about Kennedy's speech, we decided to wait so that it would appear he had some popular support," Craig said. The letter was also held so that it could be revised after the President's speech in Tennessee on Wednesday.