In The Passage of Power, Robert Caro’s fourth mammoth volume on the life of Lyndon Johnson, the newly and tragically elevated president confronts the reality that his slain predecessor’s aggressive civil rights bill is stalled in Congress. Shortly before the assassination, Johnson had argued for moving the rest of the Kennedy agenda through Congress first. “I’d move my children”–the tax and spending bills–”on through the line and get them down in the storm cellar, locked and key, and then I’d make my attack,” he told Kennedy aide Ted Sorenson. He had been ignored, and partly as a result, a strategy of delay was being deployed by segregationist House and Senate members against the whole Kennedy program. Howard Smith, the Virginian chair of the House Rules Committee, was dragging out the hearings on the bill in order to leave the Senate as little time as possible in which to pass the bill over the inevitable Southern filibuster.

The only remedy for a dilatory Rules Committee process is something called a discharge petition. If it’s signed by a majority of the House–218 members–the petition brings a bill straight to the floor, where it would surely be passed. When Lyndon Johnson took office, it was clear that the usual House procedure would not leave enough time for the Senate to pass the bill. It was likewise clear that there were not, at present, anywhere near the 218 signatures needed to spring the bill from the Rules Committee. But the signatures were the only path forward. And so Lyndon Johnson, just weeks in office, started rounding up those elusive signatures. He started with the Texas delegation, where the fate of engineering and construction firm Brown & Root’s government contracts could be counted upon to motivate members from that state. He then moved on to the Republicans, who despite their record of voting favorably on civil rights were not enthusiastic about circumventing House procedure (and, it may be guessed, not eager to see a Democratic administration end its inevitable and debilitating straddle over the issue). “If I were you, Charlie,” he told House Republican Leader Charles Halleck, the House Republican Leader, “I wouldn’t dare…go out and try to make a Lincoln Birthday speech” while “Howard Smith’s got his foot on Lincoln’s neck.”

And pressuring the Republicans might not have been effective had Johnson not met individually with the nation’s foremost civil rights leaders, including Roy Wilkins of the NAACP and Martin Luther King Jr. of the Southern Christian Leadership Conference, and urged them not just to advocate for the bill but to push Republican members specifically for the discharge petition. Johnson’s was not the first White House to throw its weight behind a strong civil rights bill, but it was the first to lean on such an obscure and unlikely lever of power to get it passed. As the number of signatures mounted, Chairman Smith relented and moved the bill to the floor. Instead of being passed and sent to the Senate in the summer, when it could be stalled until the close of the Congress, it was passed in February–which left too much time for the Southern Democrats and their few conservative Republican allies to hold out. The 1964 Civil Rights Act was passed by a crushing margin of 73-27, and yet it had barely passed at all. Pushing hard for civil rights would be a mistake, an old political hand had told the new President as they huddled together to prepare his first address to Congress. However noble the cause, it was hopeless. “Well then what the hell’s the presidency for?” Johnson reportedly responded.

Robert Caro has written five magisterial biographies over the last forty-five years. Each of them hinges on a story like that of the 1963 discharge petition, in which an obscure lever of power is seized by someone clever and determined enough to use it. In The Power Broker, a 1974 biography of Robert Moses, metropolitan New York’s long-time infrastructure titan, Caro explains how a subtle shift in the law authorizing state toll roads allowed Moses to amass a financial and planning empire within, but not accountable to, state and local governments. In 1982’s The Path to Power, his first volume on Johnson, Caro depicts the future president’s transformation, from deep in the back bench of the House, of the sleepy Democratic Congressional Campaign Committee into the Texas oil cash nexus that saved the New Deal majority in 1940. The 1990 follow-up, Means of Ascent, portrayed in minute detail the mechanics of election fraud in the Rio Grande valley in Johnson’s barely successful 1948 Senate race. And in Master of the Senate, Caro gives us an account of Johnson’s daring use of the formally powerless position of Leader to reform the seniority system in the Senate and leave a whole generation of young senators beholden to him.

Along with these gripping depictions of procedural innovation, Caro’s work is distinguished the lengthy biographical essays of secondary figures. They have included portraits, both fascinating and indispensable in the world of popular history, of the crucial, enabling associates of Moses and Johnson: the shrewd and studious Governor Al Smith, the fierce and incorruptible Speaker Sam Rayburn, the colorful “Cowboy Governor” Coke Stevenson, the genteel bigot Richard Russell, and the liberal orator Hubert Humphrey.

There is, to put it simply, no one who writes modern American biography like Robert Caro (the closest analogue I know is the late T. Harry Williams, whose definitive biography of Huey Long is the only book I’ve read that bears comparing with Caro’s finest work). His books are researched with a detail that goes beyond meticulous. He recounts opening letters so long unread that they crumbled in his hands. He tracked down the forgotten people displaced by Robert Moses’ highway projects, slept out for days in Johnson’s Hill Country to get a feel for its isolation, found new, explosive details of the 1948 election forty years after it took place. They are sweeping social panoramas and chamber dramas, driven by decades-long historical developments and by individual character. They are operatic, tending toward brisk recitative passages of plot punctuated by grand arias of theme, written in a slightly anachronistic high style but tempered with a fiercely democratic moral grounding. Part muckraker, part bard, Caro has been guided by the intuition he felt in his study of Robert Moses, that Moses “could be a vessel for something even more significant: an examination of the essential nature–the most fundamental realities–of political power.”

The Passage of Power follows Lyndon Johnson in his journey between two peaks of political power. The book opens in 1958, as Johnson gears up fitfully and ineffectively for the 1960 presidential nomination from his perch as the Senate’s universally- acknowledged heavyweight. It details his doomed attempts to hold onto his former power while drawing on new sources of it in the executive branch, before settling into the full humiliation and irrelevance of his vice-presidency. And almost half of its pages are devoted to the seven weeks following Kennedy’s assassination, weeks in which Johnson moved adroitly but swiftly to assume the office, preserve continuity with the Kennedy image and program, and to establish the policies that would, for better and worse, define his own place in presidential history. Anchoring the narrative of these six years are two of Caro’s finest set-piece sequences (it is almost fairer to compare his books to the highbrow television series, The Wire or Deadwood, than to other books): the 1960 Democratic convention and the fevered few hours before Johnson’s announcement as Kennedy’s running mate, and the fateful presidential visit to Dallas, by which time Johnson’s presence on the 1964 ticket was not at all secure. There is, of course, no doubt in any reader’s mind as to the outcome of these plots-within-the-plot (nor with the Cuban missile crisis, another fine passage). But the arguments about the events, arguments Caro has rare authority to adjudicate, are themselves part of the story, and help create the frisson of uncertainty that surrounds long-concluded facts.

There are moments when Caro pushes this tension, between writerly drama and the seeming inevitability of retrospect, a little too far. Fears that a sudden and violent presidential transition would lead to a dangerous destabilization of the Cold War–”what if tanks began to rumble forward, troops began to march?”–were understandable, but Caro marshals no actual reasons to credit them. This may in part be because Caro has never before made presidential power the focus of his work, and presidential biography, like the presidency itself, tempts its practitioners to ascribe more significance to events and people than they truly bear. Yet it is likewise true that American presidents make history, inevitably, in an entirely unique way. Among the great gifts Caro has given posterity is the story behind and between the iconic images of Kennedy’s death and burial, the story of Johnson’s swearing-in with Jackie at his side, of his tactful avoidance of the White House and the Oval Office for days and weeks after Dallas, of his ardent courtship of the Kennedy men who had so recently scorned him as “Rufus Cornpone.” While the attention of the nation was fixed, immediately and universally, on the images from Dallas and the Washington funeral, Johnson was working steadily and carefully offstage at his Executive Office Building suite and his private home to pave the way for a revolution in American politics–”a crusade for social justice on a vast new scale”– rather than a merely stable and safe transition.

And it is that revolution, along with the inevitable escalation in Vietnam that so clearly interests Caro. His portrait of Johnson brims with details, but they are all foreground. Caro’s Johnson is fully absorbed in the task of accumulating and using power. His hobbies, his affections, his idle moments, if he had any, are of no interest to Caro. Johnson appears on his pages as the kind of political athlete who wastes no thought and no effort toward any other purpose (during Johnson’s whistle-stop tour of the South in 1960, his arrival and departure was heralded by “The Yellow Rose of Texas” and by a sometimes treacherous sound system. “God bless you, Greer,” he said pulling out of a South Carolina town; “Bobby, turn off that fuckin’ ‘Yeller Rose.’”) In the end the powerful person is indistinguishable, for good and for ill, from what they do with their power.

As his immense and growing portrait of Johnson swells to its conclusion, Caro’s work leaves us with three contrasts, none fully explicit, but all of them inevitable. The first is between Johnson and Kennedy. While Caro writes with a genuine regard, even affection, for Kennedy’s personality and his political skills, it is clear that he finds Kennedy badly outmatched in his legislative conflict with the Southern faction. He quotes the NAACP’s Wilkinson calling Kennedy “very green.” While Kennedy had sent big domestic bills to the Congress, “nearly three years into the administration,” Caro points out, “not one had become law.”

By a curious shaping of historical memory, achievements that belonged chiefly to Johnson’s record were moved back, morally if not chronologically, into the Kennedy years, and the origin of the great disaster of Vietnam was pushed ahead. Robert Kennedy believed that his brother’s programs “would certainly have passed if he had lived,” and this “mantra” came to define the era in “scores of books” by people connected to the Kennedy circle, people much more adept at writing history than passing legislation. And despite his own much more passionate arguments for civil rights (Kennedy, while fully genuine on Caro’s account, was much cooler and more intellectual on the subject) this was a perception that Johnson initially encouraged. He knew very well that his Southern baggage–the “magnolia accent” that identified him with reactionary politics–left him vulnerable to a challenge in the 1964 primary, and he knew that his history of compromises within the Senate Democratic caucus from his days as Majority Leader left labor and liberals deeply suspicious of his true commitments. So Johnson explicitly re-dedicated the legislative agenda to the memory of his slain predecessor, and he indulged the ludicrous superiority complexes of the Ivy League intellectuals in Kennedy’s circle to do it.

As a result, it has taken Caro’s own Herculean labors–and the receding generational experience of Vietnam–to restore Johnson to something like the stature he deserves in progressive politics. President Obama, when presuming recently to rank his own legislative achievements among those of his predecessors, put himself behind Johnson (and, naturally, FDR). When Bill Clinton, in a moment of frustration in his first term, made the same self-evaluation, he skipped over Johnson and went straight back to Roosevelt.

Yet along with the inevitable FDR, Johnson has become an unlikely touchstone for progressive discontent with President Obama. Caro gives no indication of intending a contrast between the man who signed Medicare into law and the one who signed the Affordable Care Act, but on every point from domestic policy to international conflict to relations with Congress the comparison is inevitable. And in one sense it is not particularly helpful to Obama’s liberal critics. A common liberal complaint about Obama is that he has failed to apply rhetorical pressure, barnstorming, and other campaign-like maneuvers to pass his agenda. Whether fair or not as a critique of Obama, Johnson’s record points in a different direction. Johnson knew how to turn up the heat rhetorically, but he seems to have done it primarily to bolster his standing within his party rather than to frighten wavering conservatives off the fence. Liberals have sulked about Obama’s putatively centrist views, high-finance connections, and tendency to give too much in negotiations. The same could have been, indeed was, and said of Johnson as he strove to get the ailing Kennedy agenda off the ground. He secured the cooperation of Virginia’s arch-conservative Senator Harry Byrd, the chairman of the Finance Committee, on the stimulative tax cut measure Kennedy had proposed by sending Byrd a budget that was considerably lower what Kennedy’s budget team had wanted. And by winning Byrd’s support for the budget and the tax cut bill, Johnson opened up the procedural space for civil rights. More to the point, liberal Democrats may just never be good at identifying their friends. One of Johnson’s 1960 proxies says the Minnesota Democratic delegates “put their heads back and screeched” with mirth on being told that Johnson would be a liberal president.

Yet where a comparison between the two really does disfavor Obama is in the use of different registers of persuasion. Obama’s smart, rueful defenders have pointed to structural factors in our system, or to the fundamental circumstances of political debate, as limiting Obama’s range of motion. And not without cause. But Caro’s whole body of work is a testament to the idea that the true genius of power can circumvent those limits to a degree, through fair means or foul. Johnson was comfortable with a little demagogic rhetoric. Telling his own aides how Kennedy should argue for civil rights, he pointed out that “while he could order Negroes into a foxhole in a foreign country to fight for the American flag, he couldn’t get them into southern restaurants while they were on their way to join their units,” shaking the flagpole in his office for emphasis. And Johnson was fully willing to flatter, bully, or buy support from recalcitrant Congressmen. Obama, to the dismay of many liberal activists and observers, seems to genuinely believe much of his own “post-partisan” rhetoric. They watched Robert Gibbs go before the press to offer pallid dismissals of “politics as usual” or “Washington games” even as those unlovely methods managed to stymie the president on multiple fronts. Johnson was deeply intuitive in methods of persuasion that Obama seems to disdain. Like the best politicians, he knew that arguments will only get you so far. To paraphrase Leon Trotsky, you may not be interested in politics as usual, but politics as usual is interested in you.

The third, melancholy contrast offered by The Passage of Power is that between Caro’s work and the constrained world of publishing into which it has been prolonged. As a profile by Charles McGrath in a recent New York Times Magazine suggests, The Years of Lyndon Johnson has been a critical bonanza and a reliable bestseller but a commercial wash. The Tolstoyan extravagance of the project belongs to another age, an age of loss-leading prestige publishing, big projects, big budgets, and a healthy market for books that can, as I learned recently, literally be used to block the opposite wheel while changing a flat tire. Robert Caro has been researching Lyndon Johnson since before Barack Obama graduated high school. And he’s written what may be the most comprehensive documentation ever of an American political career. It is a feat that we may never see duplicated, at least not for the sort of audience that remains for general-interest history. One is tantalized at the thought of all the stories that will never be unearthed, the hidden maneuvers that will never come to light, and the fragile, pivotal letters that will never crumble in a historian’s hand. And there is a certain poignancy in seeing this latest volume, treating the origin of the great high period of American egalitarianism, emerge even as Johnson’s legacy is under increasingly bold attack. The Roberts Court is poised to dramatically weaken the 1965 Voting Rights Act. Paul Ryan is pursuing a widely-respected bid to void the guarantees of old-age and low-income health insurance won so painfully in 1965, while virtually eliminating the nutrition, housing, and education programs pioneered in Johnson’s administration. Ron and Rand Paul, two open opponents of even the 1964 Act, occupy comfortable niches in modern politics. The story behind that reaction–the accumulation of power that made it possible–may never be told in the detail with which we now know the revolution. Robert Caro has spent his life chasing power and showing us how effectively it can hide itself, even when it is at its most expansive. As his life’s great work moves into its last chapter, we can see power, both past and future alike, receding from our inconstant gaze.

Benjamin Dueholm

Benjamin Dueholm is a writer and Lutheran pastor working in Chicago.