Barack Obama was born in the 1960s but is not of them. Such is the constant promise of his presidential campaign. Announcing his candidacy last January, he vowed to lead a "new generation" unencumbered by the divisive struggles of the past. By last week, when a Fox News reporter asked him to define the difference between him and the Democratic front runner, Hillary Clinton, he had grown more pointed. "Senator Clinton and others have been fighting some of the same fights since the '60s," Obama replied. "It makes it very difficult for them to bring the country together to get things done."

Obama's promise—I am not the'60s—is heartfelt, but ultimately hard to believe. Just look at the gray-haired '60s idealists inside the senator's own brain trust who see him as the fulfillment of 40 years' worth of hard work. Or look at the throbbing crowds that mob the young senator, reminiscent in so many ways of the crowds that mobbed Bobby Kennedy 40 years ago. Or look at the Secret Service detail that trails Obama, a reminder of the old '60s lesson that assassination is a real threat. Obama is the '60s, whether he likes it or not.

John McCain is also the '60s. A former naval aviator who spent the latter part of the decade in a North Vietnamese POW camp, McCain uttered the best line of the 2008 presidential campaign last month in a Republican primary debate. "A few days ago, Senator Clinton tried to spend $1 million on the Woodstock Concert Museum," McCain announced. "Now, my friends, I wasn't there … I was tied up at the time." The Republican room erupted, not in laughter, but in applause. His campaign quickly took the debate clip and cut a television ad.

McCain knows what Obama should have learned by now: the '60s are impossible to escape. They will define the 2008 presidential election, just as they have defined American politics, and American culture, for the past 40 years. It is fashionable to see the boomers' '60s obsession as a reflection of their own narcissism, their inability to get over themselves. But this does not do justice to a truly traumatic decade. In the midst of adolescence, an entire generation was presented with repeated reminders of its own mortality: the Cuban missile crisis; the assassinations of Jack Kennedy, Robert Kennedy and Martin Luther King Jr.; the violence in the cities; the 58,193 Vietnam War dead. So much death and killing, too much to simply put aside.

But what about the rest of us? Nearly 162 million Americans were born after Dec. 31, 1969. More than half the country, then, knows the decade only through mythology (peace, love and liberation) or through marketing (tie-dyed T shirts at tourist shops, the Rolling Stones on oldies radio, Dennis Hopper in Ameriprise Financial ads). They rightly question what makes the '60s so special: What, after all, did the baby boomers really achieve 40 years ago? Why does NEWSWEEK commemorate 1968 instead of 1918 or 1941?

The answer: because all of us, young and old, are stuck in the '60s, hostages to a decade we define ourselves as for or against. As the pages that follow demonstrate, the '60s were not necessarily, as some baby boomers would have it, America's defining moment. But they were an era when a generation held sustained argument over the things that have always mattered most: How should America show its power in the world? What rights were owed to African-Americans, to women, to gays? What is America and what does it want to be?

These were noble questions. The debate they brought on was not. Rather, it was personal, hysterical and often terrifying. Father fought with son, black fought with white, the young fought with the old. By the end of the decade, consensus was clearly not possible, and simply restoring civilization became the goal. Subsequent generations would have to answer those essential questions.

And so the cycle has repeated itself, almost every four years. "America is back," Ronald Reagan promised in the 1980s. Blessed with the can-do attitude of the Greatest Generation and a congenital optimism, Reagan was well positioned to move the country beyond the '60s. But baby boomers saw only the Reagan who served as California governor in the 1960s, hated by young liberals, worshiped by young conservatives. Reagan and his successor as president, George H.W. Bush, ended the cold war, making the '60s dream of a peaceful world seem, for a moment, possible. But the vernacular of the 1992 presidential race, the first election after the fall of the Iron Curtain, was vintage '60s: marijuana, draft dodgers, trips to the Kremlin, San Francisco gays.

Assuming the presidency from Bush, the last of the World War II presidents, Bill Clinton promised that a "new generation" was ready for "new responsibilities." His message: the strife of the '60s was over, the decade's promises finally could be fulfilled. But it wasn't and they weren't. For the next eight years, Clinton and a cast of conservative boomer antagonists ensured that the first child of the '60s in the White House would be remembered as a '60s caricature: ambivalent toward the military, sexually promiscuous, wrapped up in himself.

In George W. Bush, Republicans found their own boomer ideal: a reactionary child of Yale in the '60s who despised that decade's elites. But he, too, promised a new way forward—a compassionate domestic policy that sought conservative means to achieve some of the '60s idealists' goals. Abroad, he promised a foreign policy that learned the lessons of Vietnam. Instead, he has delivered only divisive cultural conflict at home and a war in Iraq that miraculously managed to make every Vietnam mistake over again.

Already, the old '60s fault lines are emerging in the 2008 campaign. Earlier this fall, Mitt Romney released a Web advertisement starring the candidate's wife, talking about the trials she faced as a stay-at-home mother to five sons. "Sometimes I'd be home with those five boys, and it was rough," Ann Romney says in the ad. "He'd call home and remind me that what I was doing was much more important than what he was doing." The ad was meant to introduce Republican primary voters to Romney's family, but it shows what could be a compelling narrative for a general election campaign: family values versus free love, the order and comfort of the '50s versus the trauma and extremism of the '60s.

This old choice will not be hard for Republicans to revive if the Democratic candidate is Hillary Clinton. Clinton's '60s baggage is all around her—her 1969 Wellesley commencement speech, the pictures of big glasses and love beads, the libertine husband, the daughter they named after a Joni Mitchell song. Fifteen years in the national spotlight has taught Clinton to be wary of invoking the '60s, lest she seem like the feminist agitator her critics have made her out to be. But when provoked, she, too, falls back on '60s vernacular as she demonstrated earlier this month, when she called presidential politics an "all-boys club" after a weak performance in a Democratic debate.

So how do we finally escape the '60s in time for the election of the next president, 40 years after 1968? Not, as Obama would have it, by simply declaring the '60s done. Too many politicians have tried that before, only to be proved wrong, either by the boomer electorate or their own lingering '60s souls. The real way to move beyond the '60s is to have political leaders who are finally willing to do an honest accounting of what that fateful decade was truly about. If the civil-rights movement truly transformed America, why are our cities still segregated? If women were liberated by the '60s, why do working mothers still feel so chained down? If Vietnam taught us how to be a humble superpower, why are we still bogged down in Iraq? These will all be vital questions facing the next president. The story of 1968 demonstrates that the truly brave presidential candidate will be he, or she, who finally acknowledges the '60s have everything, not nothing, to do with us.