President Carter's report to the nation yesterday failed to address at least one key question in the Billy Carter affair and contained several shifts from previous White House statements about the matter.

The president said at his news conference that "it did occur" to him his brother might be after financial gains. Billy Carter had been seeking money from Libya for many months, but got none until after the White House had used him as an intermediary in the hostage crisis in Iran.

But the president never really dealt with the question of whether he was partly responsible for the payments by boosting Billy in the Libyans' eyes.

It also was revealed that what has previously been described as a casual conversation between the president and Attorney General Benjamin R. Civiletti on June 17 may have been a deliberate effort by Civiletti to urge the president to help solve his brother's legal problems.

There may be no real bombshells in the report, but it seems certain to leave critics with ammunition to at least question the administration's judgment on the issue.

In his 19-page written statement yesterday, the president noted that as a result of Billy's controversial statements in support of Libya in 1979, his brother's "other business activities were severely curtailed. Almost all of his scheduled television and other appearances were canceled. Billy's source of income from these public appearances disappeared, while his financial obligations continued to mount. So far as I know, Billy had no other significant sources of income."

Asked at the news conference if it ever occurred to him that his brother might be seeking financial gain from the Libyans, the president said, "It occurred to me." He then went on to recount his efforts to dissuade Billy from making a second trip to Libya in 1979. "I don't think there's anything further I could have done." If he ever asked Billy whether he got any money from Libya, he didn't say so last night.

The president insisted in his statement and news conference that he didn't see any impropriety in his brief discussion of the case with the attorney general. He said the meeting didn't last more than a minute.

In his statement on the case, however, White House counsel Lloyd N. Cutler said he was present earlier in the June 17 meeting. He noted there had been a discussion of judgeship appointments. At the end, he said, Civiletti said he had some matters he wanted to discuss with the president privately.

It was only after Cutler left that the attorney general brought up the Billy Carter case. At the same time, the president's notes also show that Civiletti brought the president up to date on another sensitive issue for the Carter White House -- the alleged use of cocaine by chief of staff Hamilton Jordan.

A few weeks before, a special prosecutor had decided the charges by owners of New York's Studio 54 disco were unsubstantiated. Civiletti commented on the "veracity and character of several" of Jordan's accusers, the report said.

Cutler's statement also said he approved release of the much-maligned July 22 administration "white paper" after checking once with the president and twice with the attorney general to make sure there had been no contact between the White House and Justice about the investigation.

Civiletti's conduct in the matter is being investigated by his department for possible improprieties. He revealed the conversation only after Cutler told him the president had found a note that reminded him of the discussion.

Earlier Civiletti had flatly denied any contact with the White House about the case.

Another shift from the former White House position on the affair came in the president's statements last night that he took responsibility for using Billy Carter as an intermediary with Libya about the hostages.

"I decided to use Billy," he said in answer to a news conference question. He then gave credit to his wife, Rosalynn, for initiating the idea.

This version, however, constrasts with the lack of any role attributed to the president earlier by his secretary, Jody Powell. Powell was the first to disclose that there had been a meeting between Zbigniew Brzezinski, the Libyan attache, Ali Houderi, and Billy Carter on Nov. 27.

At the July 22 press briefing, following release of the so-called white paper, Powell said he was not sure whether the president knew about the Nov. 27 meeting before it was held.

Two days later, at the July 24 press briefing, Powell reported "the president is not sure" whether he knew about the Nov. 27 meeting before it was held.

The president's notes, released yesterday, give a far different picture.

He reports that on Nov. 20 it was he who told Brzezinski to call Billy Carter.And he adds in another entry for that day: "I told him [Billy Carter] and Zbig to get together to discuss what message we might pass on to the Libyans."

Referring to the occurrences of Nov. 27, the president's notes record that "Billy came in, having talked to the Libyans. They are quite eager to help us . . ."

In his written statement, the president took pains to note, "The Moslem countries place great importance on family ties, and I believed that a request arranged with Billy's participation would be regarded as coming more directly from the president and might supplement the efforts already being made through normal State Department channels."

He didn't say anything in the report about the likely side effect: building up Billy in the Libyans' eyes because of that emphasis on family ties.

At another point in his written report, the president emphasized that there was "no contact in either direction between the Department of Justice and the White House concerning the conduct of the investigation, except for the routine investigative inquiries described in my counsel's report."

He did not comment on the propriety of the frequent contacts between his counsel Cutler and his brothers lawyers.

In a 12-page statement White House counsel Cutler recounts seven instances of conversations with Billy Carter's lawyers, Henry Ruth and Steven Pollak, about the progress of their negotiations with the Justice Department. He was doing so, he said, so the president would know and he could prepare whatever comment the White House would make to the press.

One statement by the president last night that raised eyebrows was his twice-repeated recollection that he was not aware Billy Carter "was planning the [1978] trip [to Libya] until shortly before his arrival."

The report of the White House counsel, released yesterday, outlines approaches to the State Department and the White House by either Billy Carter or his associate, Henry (Randy) Coleman, before the 1978 trip.

The National Security Council staff members, for example, recall briefing Coleman in August 1978 about Libya at the request -- they recall -- of the president's appointment secretary, Phillip Wise.

In that briefing the White House aides suggested the trip be delayed because of the Camp David meetings. Wise has said he does not remember requesting the briefing.

Coleman also called the State Department's North Africa desk before the 1978 trip to ask about his and Billy Carter's travel plans.

The State Department officials then informed White House aide Thomas Beard of the proposed trip.

Thereafter, according to James V. Bishop, one of the State Department officials aware of Billy Carter's plans, the president's Cabinet secretary, Jack Watson, called to ask about the Billy Carter trip.

In other words, the president maintains that he knew nothing of his brother's plans to visit Libya although people close to the president did.