Part of the answer lies in the title for the series, The Years of Lyndon Johnson. The volume under review, The Passage of Power, like its predecessors, The Path to Power (1982), Means of Ascent (1990), and Master of the Senate (2002), provides a front-row view of America’s political process and society. Perhaps even more compelling, however, is the complex, towering figure of Johnson himself.

The Passage of Power commences with the 1960 presidential campaign. Johnson is then Democratic leader in the Senate. Unexpectedly, he becomes vice-presidential candidate on the Kennedy ticket, which wins the election. On 22 November 1963 Kennedy is assassinated in Dallas and Johnson succeeds to the presidency. The volume ends in mid-1964, when his transition to the office has, for practical purposes, been completed.

The cliché ‘roller-coaster ride’ is apt for this period (except to the extent that it suggests pleasurable thrills, secure in the knowledge all the time that the ride will end safely and happily). Caro gives an illustrative vignette of Johnson’s dominance in the role of Majority Leader:

Prowling the Chamber during debates, he would put a long arm around a senator, grasp his lapel firmly with the other hand, put his face very close to his colleague’s as he tried to persuade him. His hands never stopped moving, patting a senator’s shoulder, straightening a senator’s necktie, jabbing a senator’s chest, gesturing expressively, his face breaking into a grin if the senator agreed to the proposition being made, turning cold and hard if he didn’t.

The 1960 Democratic National Convention

Johnson had grown up in a household of poverty and humiliation in the Hill Country of Texas, his father a state politician bankrupted in a failed cotton- farming venture. Local families brought charity in the form of cooked dishes when there was no money to buy food. Johnson fiercely desired the Democratic nomination for president in 1960, but his deep fear of failure kept him from campaigning openly until very late. Much to the consternation of the liberal wing of the Democratic party and the labour movement, John Kennedy offered him the vice-presidential spot on the ticket. Robert Kennedy went three times to Johnson’s hotel room to persuade him to withdraw, a major episode in the saga of visceral hatred between the two men. In the event, Johnson campaigned effectively and helped carry Southern states that were essential to Kennedy’s narrow victory.

Under the United States Constitution, other than succeeding to the office of president if it becomes vacant, the only function of the vice-president is to preside over meetings of the Senate. The recent prominence and influence of George W. Bush’s vice-president, Dick Cheney, is very much the exception. The old joke has it that a mother had two sons: one ran away to sea and one became vice-president, and neither was heard of again. Franklin D. Roosevelt’s first vice-president, John N. ‘Cactus Jack’ Garner, a Texan like Johnson who was also a mighty figure in Congress, memorably said that the job was ‘not worth a bucket of warm piss’.

And so it was for Johnson. His period as vice-president was one of humbling irrelevance. In the words of Arthur M. Schlesinger Jr, he ‘seemed to have faded astonishingly into the background’. A poignant incident illustrates this:

And once he came into the Democratic cloakroom, where, for eight years, he had been the cynosure of senators’ attention, where he stood dispatching senators for a speech or a parliamentary maneuver, leaning over to hear as Bobby Baker or some senator whispered in his ear, senators clustered around him, trying to catch his eye. This time, when he came in, a few senators were in the cloakroom, sitting in armchairs or on the sofas, reading newspapers or chatting. He greeted them. They greeted him back. Then Lyndon Johnson stood in the centre of the cloakroom for a few minutes. No one stood up to talk to him. No one invited him to sit down. One of the men who was there that day says, ‘I don’t think he ever came into the cloakroom again.’

The diaries of Evelyn Lincoln, Kennedy’s secretary, record that in the ten and a half months of 1963 immediately prior to the assassination Johnson was alone with the President for a total of one hour and fifty-three minutes. Socially he was excluded from the glittering milieu that surrounded the Kennedys, ‘the Harvards’ as Johnson bitterly referred to them. They referred to him as ‘Colonel Cornpone’.

All this changed on 22 November 1963. The immediate circumstances were inauspicious for Johnson, to say the least. There had been speculation, which Caro’s evidence suggests was well based, that Johnson would be dumped from the Democratic ticket for the 1964 election. More importantly, Johnson’s assistant and protégé Bobby Baker was caught up in serious corruption allegations, which were the subject of a Senate committee hearing at the time. Life magazine had an investigative team working on an exposéof Johnson’s wealth. All his working life had been spent in modestly paid government positions: teacher, congressional aide, congressman, senator, vice-president. Yet he was worth many millions.

Caro describes the chaos following the assassination in almost minute-by-minute detail. At the hospital, Johnson was not told of Kennedy’s death for half an hour. Nevertheless he exercised his new authority without hesitation. He insisted on taking the oath of office immediately in Air Force One, rather than flying back to Washington first. He carefully choreographed the famous photograph of the oath-taking, with Jackie Kennedy in her blood-stained pink suit. Characteristically, he insisted that the oath be administered by a local Federal District judge, Sarah T. Hughes, who was located after a frantic search. As vice-president he had sought the appointment of Mrs Hughes, only to be rebuffed by Bobby Kennedy. Humiliatingly, Johnson had to rely on the matchless authority of fellow Texan and House Speaker Sam Rayburn to get the appointment through.

The complete dominance and self-confidence with which Johnson asserted his authority upon his return to Washington emerges from Caro’s account of preparations for the new president’s address to the joint session of Congress on the Wednesday after the assassination. He was working on his speech with Abe Fortas, Hubert Humphrey, and other Johnson allies until two-thirty in the morning. Caro quotes the account of Fortas:

‘One of the wise, practical people around the table’ urged Johnson not to press for civil rights in his first speech, because there was no chance of passage, and a President shouldn’t waste his power on lost causes – no matter how worthy the cause might be. ‘The presidency has only a certain amount of coinage to expend, and you oughtn’t to expend it on this,’ he said.

‘Well, what the hell’s the presidency for?’ Lyndon Johnson replied.

The speech turned out to be a triumph. Newsweek had informed its readers that, while Johnson could be ‘charming, informed and persuasive in man-to-man talk, he often seems corny and tedious in public address’. His usual style was dogmatic, loud, overbearing, and too fast. But with his immense capacity for self-discipline when needed, he had the speech retyped in one sentence paragraphs and annotated it with ‘pause’ and ‘pause pause’ throughout.

On civil rights, to the obvious discomfiture of leading Southern senators, he discarded the ‘wise, practical’ advice and said:

First, no memorial oration or eulogy could more eloquently honour President Kennedy’s memory than the earliest possible passage of the civil rights bill for which he fought so long. We have talked long enough in this country about equal rights. We have talked for a hundred years or more. It is time now to write the next chapter, and to write it in the books of law.

This volume takes us up to the passage of the Civil Rights Act on 2 July 1964, and notes Johnson’s consummate skills in overcoming the obstruction of conservative Democrat senators (and not a few Republicans, whom Johnson embarrassed by reminders that they belonged to the party of Lincoln). Johnson’s great Voting Rights Act of 1965 lies ahead, as does the engulfing catastrophe of Vietnam. The story of those times in Caro’s fifth volume will be eagerly awaited, however ‘bloated’ it might be.