WASHINGTON — It was fleeting — just 30 seconds — in Barack Obama's long campaign for the Democratic presidential nomination.

But it heralded the turning point in his vanquishing Hillary Clinton.

It was a TV ad showing the candidate reaching to grasp outstretched hands, an image long associated with the 1968 campaign of Robert Kennedy. Its message was simple: "Text HOPE to 62262."

The ad ran during the Super Bowl broadcast.

Just two days later, in the 23 states the

Democrats contested in the Super Tuesday primaries and caucuses, Obama denied Clinton her planned knockout punch. He then racked up 11 straight wins over the following weeks, building up a lead in nominating delegates that would survive a late surge by Clinton.

The ad reflected Obama himself: young, handsome, hip, a tech-savvy politician offering hope to voters weary of war, worried about their economic future and concerned about the direction of their country.

But it also represented an evolution — perhaps revolution — in the arts and sciences of presidential politics, part of a campaign that fit a cool and natural candidate perfectly, mixing old and new media and harnessing the power of new technologies and the Internet as never before to raise money and to unleash the organizing and communications talents of volunteers.

Those who sent the HOPE text message to 62262 were welcomed into the electronic tent of the Obama campaign with issue information tailor-made for them and an invitation to join the unprecedented army of Obama volunteers.

That army, which included record numbers of new voters, helped Obama become the presumptive Democratic nominee in a primary campaign that some political analysts believe is a new model for presidential politics.

Even so, without an inspiring candidate, a message that resonates, a coherent strategy, the ability to raise money and a little luck, a model is just a model.

Obama's campaign seemed to have it all. It didn't hurt, either, that Obama planned a marathon run

for the nomination, not the sprint through the

Super Tuesday contests that was the core of Clinton's strategy.

Where Clinton concentrated on the big primary states, with their huge number of delegates, the Obama camp paid as much attention to the smaller caucus states that the Clinton campaign all but ignored.

"They basically ceded all the caucus states to us, which gave us a great advantage," Obama chief strategist David Axelrod told reporters.

Nowhere did the Obama campaign concentrate its efforts more than in Iowa, which kicked off the voting in the Democratic contest.

Obama's advisers reasoned that if Clinton won Iowa, she could become the inevitable candidate, as her top strategist, Mark Penn, had argued in a highly publicized memo.

"By winning Iowa, [Obama] turned the race into a two-candidate contest, demonstrated that Clinton was not inevitable and that he could comfortably take a state where African-American voters are only a very small minority," said Peverill Squire, a longtime Iowa political analyst now at the University of Missouri.

The Obama campaign also understood the rules of the Democratic Party better than the Clinton campaign, recognizing that the awarding of delegates proportionally, often on the basis of congressional districts, meant a candidate could even lose the popular vote in a state but win the most delegates.

It occurred just that way in Texas, one of the states that Clinton hailed as a comeback following the loss of 11 straight contests to Obama in February. In the end, Obama got more delegates from Texas than Clinton.

Obama also recognized that he could not win the Democratic nomination with just Democratic voters. So while reaching out to independents, Republicans and the young, he also sought to grow new voters. The result was record turnouts in virtually every state.

Nothing about the Obama campaign surprised political analysts more than its unprecedented ability to raise money, especially from small donors, using the Internet. It astonished even Joe Trippi, who helped pioneer Internet fund-raising and grass-roots organizing for Howard Dean's presidential campaign in 2004.

"We proved you could fly. Obama really is landing a man on the moon," said Trippi.

Obama raised more than $265 million for the primaries from more than 2 million people, many of them first-time donors giving small amounts.

Clinton, on the other hand, raised $215 million, but mostly from wealthy individuals making the maximum legal contribution of $2,300 for the primaries and $2,300 for the general election.

Obama's money edge allowed him to outspend Clinton not only on television ads but also in putting together traditional field organizations in states across the country that Clinton could not afford to contest.

Still, one of the most remarkable things about his campaign was its savvy use of the Internet and new media, not only to raise money and reach new audiences but also to organize grass-roots volunteers.

The campaign ceded authority to the volunteers to forge their own electronic connections with other supporters through social-networking sites, such as Facebook and MySpace.

Through it all, Obama seemed to learn from his mistakes, big and small.

Losing the New Hampshire primary forced him to begin planning for the long haul rather than keep pushing for an early knockout of Clinton.

In the spring, when the controversy erupted

over the anti-American statements of his former minister, the Rev. Jeremiah Wright, Obama not only distanced himself from his ex-pastor, but also delivered a thoughtful speech on race relations in America.

His loss of working-class white voters in the final stages of the primary season has prompted him to renew his appeals to them. And his campaign speeches mix in more red, white and blue patriotism than before, matching the flag lapel pin he has resumed wearing.

Ultimately, Obama had the good fortune of having Clinton as an opponent, despite the advantages of name-recognition, organization and fund-raising she brought to the contest as the front-runner.

At the outset, her campaign misjudged the mood of the electorate, stressing experience over change. She also overspent in Iowa, a contest one of her deputies had urged her to bypass.

In the end, Obama also likely benefited from Clinton and Bush fatigue — the fact that a Clinton or a Bush had been on the ticket of a national party in every election since 1980.