A lawyer for CBS News said yesterday that retired Army Gen. William C. Westmoreland's $120 million libel suit against the network is beginning to "unravel" because the general's lawyers have said they no longer will contest accusations that he deceived the public and Congress about enemy troop strength in Vietnam.

Instead, Westmoreland's legal team apparently will argue that his reputation suffered from sections of a CBS documentary that accused him of misleading President Lyndon B. Johnson, his commander in chief, into believing that the enemy was running out of men only a few months before the communists' massive Tet offensive in 1968.

Dan Burt, Westmoreland's lawyer, said he "absolutely" did not mean to imply by this intended shift in focus of the trial that the general deceived the public and Congress about troop strength.

He said narrowing the case would make it apply only to the general's "legal duty" to the president during Vietnam. As for the public, Burt told U.S. District Court Judge Pierre Leval here on Thursday: "There were situations in which intelligence had to be protected."

The trial, which starts Tuesday, is expected to draw some of the key figures from the Johnson administration to testify about Vietnam. At issue is whether CBS showed a "reckless disregard for the truth" when the network produced "The Uncounted Enemy: A Vietnam Deception," aired in January 1982.

CBS lawyer David Boies, who said he believes that Westmoreland's case is "beginning to unravel," said narrowing the focus of the case would mean that the trial could concentrate on testimony from top policy makers from the Johnson war years, many of whom are witnesses favoring Westmoreland.

Burt, who denied that the trial would be an ideological battle on the Vietnam war, portrayed himself as a liberal working for the Capitol Legal Foundation, funded by a number of prominent conservatives. Saying he is a member of the American Civil Liberties Union, Burt told reporters in words echoing the period of Wisconsin Sen. Joseph R. McCarthy: "I am not now, nor have I ever been, a conservative."