A 2003 Gallup poll indicated that nearly 20% of Americans suspected Lyndon B. Johnson of being involved in the assassination of Kennedy. About the book: https://www.amazon.com/gp/product/1629144894/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1629144894&linkCode=as2&tag=ub066-20&linkId=3566e412f845e787ef50c212b9ceac5f
Most current theories put forth a criminal conspiracy involving parties as varied as the CIA, the Mafia, anti-Castro Cuban exile groups, the military industrial complex, the Israeli Mossad, sitting Vice President Lyndon B. Johnson, Cuban President Fidel Castro, FBI director J. Edgar Hoover, the KGB, or some combination of those entities. In an article published prior to the 50th anniversary of Kennedy's assassination, author Vincent Bugliosi estimates that a total of 42 groups, 82 assassins, and 214 people have been accused in conspiracy theories challenging the "lone gunman" theory.
Critics of the Warren Commission have accused Johnson of plotting the assassination because he "disliked" the Kennedys and feared that he would be dropped from the Democratic ticket for the 1964 election. With his 1968 book, The Dark Side of Lyndon Baines Johnson, Joachim Joesten is credited as being the first conspiracy author to accuse Johnson of having his role in the assassination. According to Joesten, Johnson "played the leading part" in a conspiracy that involved "the Dallas oligarchy and ... local branches of the CIA, the FBI, and the Secret Service." Other assassination authors who have indicated there was complicity on the part of Johnson include Jim Marrs, Ralph D. Thomas, J. Gary Shaw, Larry Harris, Walt Brown, Noel Twyman, Barr McClellan, Craig Zirbel, Penn Jones, Jr., and Madeleine Brown.
In 2003, researcher Barr McClellan published the book Blood, Money & Power. McClellan claims that Johnson, motivated by the fear of being dropped from the Kennedy ticket in 1964 and the need to cover up various scandals, masterminded Kennedy's assassination with the help of his friend, Austin attorney Edward A. Clark. The book suggests that a smudged partial fingerprint from the sniper's nest likely belonged to Johnson's associate Malcolm "Mac" Wallace, and that Mac Wallace was, therefore, on the sixth floor of the Depository at the time of the shooting. The book further claims that the killing of Kennedy was paid for by oil magnates, including Clint Murchison and H. L. Hunt. McClellan states that the assassination of Kennedy allowed the oil depletion allowance to be kept at 27.5 percent. It remained unchanged during the Johnson presidency. According to McClellan, this resulted in a saving of over $100 million to the American oil industry. McClellan's book subsequently became the subject of an episode of Nigel Turner's ongoing documentary television series, The Men Who Killed Kennedy. The episode, "The Guilty Men", drew angry condemnation from the Johnson family, Johnson's former aides, and former Presidents Gerald Ford and Jimmy Carter following its airing on The History Channel. The History Channel assembled a committee of historians who concluded the accusations in the documentary were without merit, and The History Channel apologized to the Johnson family and agreed not to air the series in the future.
Madeleine Brown, who alleged she was the mistress of Johnson, also implicated him in a conspiracy to kill Kennedy. In 1997, Brown said that Johnson, along with H. L. Hunt, had begun planning Kennedy's demise as early as 1960. Brown claimed that by its fruition in 1963, the conspiracy involved dozens of persons, including the leadership of the FBI and the Mafia, as well as prominent politicians and journalists. In the documentary The Men Who Killed Kennedy, Madeleine Brown and May Newman (an employee of Texas oilman Clint Murchison) both placed J. Edgar Hoover at a social gathering at Murchison's mansion the night before the assassination. Also in attendance, according to Brown, were John McCloy, Richard Nixon, George Brown, R. L. Thornton, and H. L. Hunt. Madeleine Brown claimed that Johnson arrived at the gathering late in the evening and, in a "grating whisper," told her that the "...Kennedys will never embarrass me again—that's no threat—that's a promise." In addition, Brown said that on New Year's Eve 1963, she met Johnson at the Adolphus Hotel in Dallas and that he confirmed the conspiracy to kill Kennedy, insisting that "the fat cats of Texas and [U.S.] intelligence" had been responsible. Brown reiterated her allegations against Johnson in the 2006 documentary Evidence of Revision. In the same documentary, several other Johnson associates also voiced their suspicions of Johnson.