NEW YORK -- President John F. Kennedy openly scorned the notion of Vice President Lyndon Baines Johnson succeeding him in office, according to a book of newly-released interviews with his widow, former first lady Jacqueline Kennedy.
In the interviews, she also called civil rights leader Martin Luther King Jr. "terrible," "tricky" and "a phony."
"This book shows Jackie Kennedy unplugged," historian and CBS News analyst Douglas Brinkley told "Early Show" co-anchor Erica Hill Monday.
He said, "A lot of the rawness of her feelings, I think, as a young woman -- she's is only in her 30s when she is doing these tapes in 1964 -- is very different from the more poised and discreet Jackie Kennedy we got to know in the 1980s and 1990s."
She said her husband and his brother, then-Attorney General Robert F. Kennedy, a longtime LBJ antagonist, even discussed ways to prevent Johnson from winning the Democratic nomination in a future contest.
The book, "Jacqueline Kennedy: Historic Conversations on Life with John F. Kennedy," includes a series of interviews the former first lady gave to historian and former Kennedy aide Arthur M. Schlesinger Jr. shortly after her husband was assassinated on Nov. 22, 1963.
Over seven sessions, she recalled conversations on topics ranging from her husband's reading habits to the botched Bay of Pigs invasion in Cuba.
The book is scheduled to be published Wednesday by New York-based Hyperion Books.
Its release comes on the 50th anniversary of Kennedy's first year in office.
The Associated Press bought a copy last week.
JFK chose Johnson, a Texas senator and former political rival, as his running mate in 1960 because, Brinkley pointed out, JFK felt he needed Johnson on the ticket to win Texas in the presidential election. But Jacqueline Kennedy told Schlesinger in the 1964 interviews that her husband often fretted about the prospect of a Johnson presidency.
"Jack said it to me sometimes. He said, 'Oh, God, can you ever imagine what would happen to the country if Lyndon were president?"' she recalled. "And Bobby told me that he'd had some discussions with him ... do something to name someone else in 1968."
Johnson was sworn in as president after JFK's assassination and was elected to a full term in 1964. He declined to seek re-election in 1968.
Jacqueline Kennedy also indicated that her husband was highly skeptical about victory in Vietnam, a central battleground of the Cold War and the conflict that brought down Johnson's presidency.
She said JFK, a Democrat, had named Henry Cabot Lodge, a Republican he had defeated for a Massachusetts Senate seat in 1952, as U.S. ambassador to Vietnam because JFK was so doubtful of military success there.
"I think he probably did it ... rather thinking it might be such a brilliant thing to do because Vietnam was rather hopeless anyway, and put a Republican there," Jacqueline Kennedy said.
JFK increased the U.S. presence in Vietnam throughout his brief administration, adding military advisers to help train the South Vietnamese military. Johnson, as president, would later commit ground troops to the conflict despite initial promises not to. Historians still debate whether Kennedy would have done the same.
Jacqueline Kennedy spoke skeptically of King.