For a people whom Tocqueville described as living eternally in the future, we Americans do quite a lot of remembering. Eight weeks ago, it was Martin Luther King Jr., who has been gone longer than he was alive. Now we enter the season of remembrance for a former New York senator, Robert F. Kennedy, a season made all the more poignant by the depressing news that the Liberal Lion, Ted Kennedy, is suddenly and unexpectedly a lion in winter.

R.F.K.'s busy life ended on June 6, 1968; barely, it seemed, after eulogizing King with one of the most arresting (and spontaneous) speeches in American history. It feels safe to say that no one else in American public life would have quoted Aeschylus' Agamemnon to an angry black crowd on the day that King was killed. It also seems, with the insight that time has brought, that Kennedy was trebly reflective that night in Indianapolis, thinking about his assassinated brother, about M.L.K. and perhaps even about his own demise, which many of his friends felt to be imminent. The verses he chose that evening still help as we try to make sense of the void left by this most unusual politician:

Even in our sleep, pain which cannot forget

Falls drop by drop upon the heart,

Until, in our own despair,

Against our will,

Comes wisdom

Through the awful grace of God.

"Against our will" may be the key phrase, aptly summing up the awkwardness and ultimate valor of Robert Kennedy's run for the presidency in 1968. The gambit faced enormous obstacles from the start, including R.F.K.'s early ambivalence and the challenge of running against several challengers, in different locales, with little advance warning. It lasted a mere 82 days -- hardly any time at all measured by the Homeric contest joining Barack Obama and Hillary Clinton -- but it brought out such good qualities in the candidate and the country that it simply refuses to expire. As long as Americans feel unrepresented by their representatives -- in other words, forever -- the Kennedy campaign of 1968 will endure as example of how, in the candidate's own words, we can do better.

A good new book -- along with a splashy cover story in Vanity Fair -- brings it all back home. One could fairly question the assumption that a new book is needed, for we have no shortage of commentary about the campaign. Even before he ran, there were books predicting that he would; then there was the race itself and all the press coverage; and then a flood of retrospective books after it came to an abrupt end in a kitchen pantry of the Ambassador Hotel in Los Angeles. Many are excellent, including touching memoirs by reporters who covered the campaign (David Halberstam, Jules Witcover), and broader canvases painted by friends and aides closer to the man himself (Arthur Schlesinger Jr., William vanden Heuvel, Jean Stein and George Plimpton). A spate of recent biographies has added to the pile, and yet the need to understand persists, not only because of the candidate's magnetism but because so many of the questions about America he dared to ask that spring remain unanswered.

Thurston Clarke has written about the Kennedys before (a good study of J.F.K.'s Inaugural Address), and brings familiarity and efficiency to the task. Unlike many R.F.K. books, The Last Campaign has comparatively little on his early life and his long service at the side of his older brother. That's a shame, because the start of his career was so arrestingly different from his candidacy, but the advantage is that we move very quickly into the race itself, with its roller-coaster swerves and lurches. Mr. Clarke advances at a sprightly pace, has a keen eye for detail and captures not only the externals but the fascinating inner dynamics of the contest.

Paradoxes were not hard to find in 1968, beginning with a photogenic candidate who could be terribly shy, a man of courage who waited too long to enter the race, and a critic of violence who plunged into crowds again and again, seemingly courting disaster.

As Mr. Clarke reminds us, it was anything but a coronation. When he returned to Washington from his first campaign trip, he found no one at the airport to greet him, and joked "even my driver has deserted me." Sometimes he had to remind his audiences to clap, and at the beginning, he struggled against verbal miscues (he asked the people of Kansas to work for him in their "villages and hamlets") and serious shortages (his aides were forced to hand out leftover buttons from his Senate races).

Those were the good problems. The more serious ones included the vitriolic hatred he aroused, both within and without the Democratic party he was trying to lead. Lyndon Johnson and J. Edgar Hoover did all they could to undermine him; establishment politicians and newspaper owners taunted him for his youth and his long hair (a headline in the Indianapolis Star: "Unfit, Unshorn, Unwanted"). Hate mail poured in from both the right (outraged by his criticism of the Vietnam War) and the left (furious that he was not moving faster). A major drama of the book lies in the growing dread -- fanned by quotations from friends, rivals and the candidate himself -- that a nameless assassin was lurking in the throngs. "I'm afraid there are guns between me and the White House," he told an aide. Yet his indifference to danger, and his electric connection with the huge numbers of people who came out to see and touch him, was essential to his appeal.

Given these challenges, it's understandable that he began to move in unconventional directions, ignoring the normal rules of politics to devise new sorts of events, a sort of "jazz politics" with improvised remarks, self-mocking jokes, long sessions with crowds, and extensive Q&A sessions everywhere he went. Ever the contrarian, he would articulate angry black concerns to angry white audiences, and vice versa. Amazingly, he appealed to both, drawing in George Wallace supporters as well as Black Panthers. He would go hundreds of miles away from where the votes were to court Native Americans on reservations; children and elderly in ghettos; and remote rural Americans who've barely seen a presidential candidate since. He flouted an essential rule in American politics (never quote a French philosopher under any circumstances), citing Camus and Sartre with reckless abandon, and then immersing himself again in the crowd. Has there ever been a greater existentialist?

Mr. Clarke captures this transformation with skill, showing R.F.K. emerging, page by page, into a brilliant and utterly iconoclastic politician over those short months on the trail. Though his anguish over Dallas never left him -- and may have explained his desire to taunt danger -- Mr. Clarke argues, persuasively, that R.F.K. was a completely different kind of Kennedy, willing to say things and go places that his more carefully scripted brother never would have.

Conservative Indiana turned out to be the crucible for these growing talents. Kennedy campaigned well and won 10 of its 11 districts. From that character test, he grew stronger, and despite a setback in Oregon, he seemed poised to win the nomination with a victory in the California primary. That he was killed at this supreme moment of vindication, for so little reason, still comes as a plot twist so outrageously unacceptable that Shakespeare wouldn't have dared inflict it on his public.

Hauntingly, he had predicted, just before his victory, that "Los Angeles is my Resurrection City."

The religious wording almost fits -- for as he wandered deeply into the invisible parts of America that lay below the poverty line, he began to seem like someone out of a medieval pilgrim's tale, part Christian mendicant, part Greek philosopher. Just as J.F.K. had loved Camelot, so R.F.K. loved Man of La Mancha, and throughout this book there's a sense of the quixotic journey, and the beautiful world that might have come into existence if the pilgrimage had reached a better terminus. One witness cites the "phantom presidency" that all of R.F.K.'s staff identified with, like the memory of an amputated limb, long after his assassination.

R.F.K. would surely have resisted the tendency to idealize him. As Aeschylus wrote, "know not to revere human things too much." It remains unclear -- despite several tantalizing crumbs that Mr. Clarke leaves in the reader's path -- that he would have won the nomination at Chicago without the support of the ultra-superdelegate, Mayor Richard Daley. Even if he'd won, it's naïve to assume that any presidency would have been successful at the end of the 1960s, though it's hard to imagine one that would have turned out worse than Richard Nixon's.

The unfinished feeling behind this story of a work eternally in progress is what leaves so many readers and voters wanting to know more about Robert Kennedy. It was a feeling that profoundly animated the Clinton White House, especially near the end, as new initiatives were designed to support the same people Kennedy had reached out to. It still animates the supporters of both Democratic candidates (a rare point of convergence), for R.F.K. can be plausibly argued to be in the camp of either Barack Obama or Hillary Clinton, depending on whether one is talking about his appeal to black voters, rural voters, Appalachians -- or the simple fact that he was a New York Senator running against two other Senators. Her remark was unfortunate, but a candidate with a famous last name, accused of ruthlessness, running against most of the party and the media establishment, with the support of blue collar voters and other outliers -- that's vintage R.F.K.

Of course, 2008 is not 1968 (thank God). But still, that revolutionary moment lives on in powerful ways, often when we least expect it. The same day that the news hit about Ted Kennedy, a small story ran in the Bloomberg News that the town of Greenwich, Conn., had been presented with an application to build a personal residence with a 12-car garage and 26 toilets. Sometimes it's not so difficult to understand why Americans remain fascinated with Robert Kennedy.

Book reviewed in this article

Thurston Clarke, The Last Campaign: Robert F. Kennedy and the 82 Days that Inspired America, 321pp., Henry Holt.