By the end of his presidency in 1968, Lyndon Johnson - the man thrust into the Oval Office after the murder of John F Kennedy - was troubled in his sleep by nightmares in which he felt paralysed.
At the time, US troops were making little progress in Vietnam and the anti-war movement at home was growing. Then two prominent figures - the civil rights leader Martin Luther King and Senator Robert Kennedy - were shot dead.
Here, Professor of International History David Reynolds - from the BBC Radio 4 series America, Empire of Liberty - looks at President Johnson's last days in the White House.
Photos courtesy Getty Images and AP. Includes music by Jimi Hendrix Experience, Tom Paxton, Simon and Garfunkel, and The Lemon Pipers.
Slideshow by Paul Kerley. Publication date 18 June 2009.