Senator Clinton squeaked past the post last night. In the expectations game that early primary races represent, and in the light of the polling which put Senator Obama up to a dozen points ahead, the result in New Hampshire counts as a resounding victory.

But it was too close for comfort for the Clintons. There will be an urgent and anguished post mortem to explain why the race came so close, and there will be changes at the top of the Clinton campaign. Senator Obama has given the Clintons a scare they do not want repeated in Michigan, South Carolina, and Nevada next week.

Few people even a month ago foresaw how close the Democratic race would become. Something extraordinary has been going on, but it is by no means clear what it is. What is behind the failure of Mrs. Clinton, the “inevitable” frontrunner for so long, to coast her way to the nomination after so much hard work, treasure, and planning? Above all, how best to account for Obama-mania? At first glance the enthusiasm for the Illinois senator might suggest that the influence of the baby boomers upon American politics is fast coming to an end. The influence of the sex, drugs, and rock and roll generation may, perhaps, have run its course. Those like the Clintons who benefited from the hopes and aspirations of the blue jeaned flower children who headed to Woodstock would have to move out of the fast lane and make way for the young.

That Mr. Obama appeals to young voters, both registered Democrats and Independents, is evident. You can see it in the long lines of young faces waiting in the cold to hear him speak. You can tell from the size of the turnout, where record numbers of new voters have been taking part in grass roots democracy for the first time. Not since the flowering of the new democracies of South Africa and Iraq have so many so eagerly come out to cast their votes.

The boomers’ children, the YouTube generation, are in their way as coherent a group as their parents, with similar appetites in music and fashion, shared mostly liberal social attitudes, and networks of friends that, thanks to new technology, transcend traditional social groups and geography. They clearly see something they like in the Senator from Illinois.

But they are not alone. So do the boomers.

For the last two elections, contrary to their natural predilections, registered Democrats have been so determined to win back power that they have been prepared to be guided by their heads not their hearts. The experiment has not been a happy one. After the depression of Al Gore’s defeat at the hands of the Supreme Court, an election that he largely lost for himself, came the uninspiring campaign and rout of John Kerry, another safe bet who contributed to his own undoing.

In Iowa, it seems, many Democrats were not prepared to suppress their nature for a third time. If they were to lose in November, they would rather go down to defeat with a candidate they could admire. Mr. Obama not only inspires by his talk of change, he is a glamorous and romantic figure. He riffs about a utopian world where anything is possible and all wrongs can be righted. Like Ronald Reagan, he lifts the spirits with his words and makes the very notion of being American something to be excited about.

Unlike those who lived through the assassinations of the Kennedy brothers and Martin Luther King, Mr. Obama has no compunction about invoking heroic figures from the Democratic near past. He has conjured up the ghost of President Kennedy, as he did yesterday when he bristled at Mrs. Clinton’s taunt that his boasts of being the best agent of change demand a “reality check.” “Imagine John F. Kennedy looking up at the moon and saying, ‘Darn, that’s far,'” he said, to laughter.

In sharp contrast to Mr. Obama, Senator Clinton is the sensible candidate. She is disciplined and competent. She is dogged and determined. But she is not exciting, nor is she inspirational. She is everything the unabashed progressives of the Beatles generation hate. She is the establishment. She is a grown up. Even President Clinton appears in recent days to have lost the youthful sparkle that has made it so thrilling in the past to be in his company.

The Clintons have been unnerved by the rise of Mr. Obama. Senator Clinton’s frustration has been palpable and led to her tearful moment on Monday, an emotional event which may have helped tip women to vote for her. President Clinton’s response to the threat to his wife’s rise has been atypically unattractive, with a testy performance on Charlie Rose before Iowa voted followed by an angry tirade against the press this week for not having scrutinized Senator Obama’s scant resume.

In Iowa, Senator Obama romped ahead, winning votes not only from young Democrats but from their idealistic parents. Mrs. Clinton, it seemed, had been placed in the dumpster of history as yesterday’s woman. But something happened in the last three days, as Clinton campaign staff began noticing. Mrs. Clinton looked beaten and bowed, but New Hampshire voters were, apparently, weighing whether Iowa’s passion for Mr. Obama would translate into a win in November.

The voting patterns that emerged last night showed support dividing along similar lines to the split in 2004 between Howard Dean and Senator Kerry, with Mr. Obama inheriting youthful liberal Democrats and Senator Clinton impressing older, more moderate voters. The boomers, it seems, took fright at the Obama wave in the closing days of the hustings, alarmed perhaps at the lack of due diligence about the Illinois senator, and how vulnerable he might turn out to be if the Republicans turned on him, as they surely would.

The oldies returned to the Clinton fold, not with any great conviction, perhaps, but having learned something from the sixties about false prophets and forlorn hopes. Clapton, it turned out, was not God, nor was John Lennon Jesus, nor the Maharishi the hope of the world.

Mr. Obama now has a most difficult task ahead, to reignite the passions of a one man movement which have been dampened by the victory of experience over hope.

nwapshott@nysun.com