CHICAGO – They missed classes, skipped sleep and parties. Thousands spent countless hours instead knocking on doors to make a case for Barack Obama, the man who would be elected the next president of the United States. And many more young Obama supporters stood in line for hours to vote, some for the first time.

Tobin Van Ostern, a senior at George Washington University, knew it was all worth it as he and hundreds of other students raced down to the White House, cheering and chanting after their candidate’s win Tuesday night.

“It was one of the most incredible feelings I have ever felt,” said Van Ostern, the national co-director of Students for Barack Obama. “People were all so hopeful for the future.”

The night was a huge moment for Obama, of course. But some say it also was a defining moment for a generation of youth who played a key role in electing him.

Exit polls show that 18- to 29-year-olds voted for Obama by a more than 2-1 margin, boosted by particularly strong support from young African-Americans, Hispanics and Asian-Americans.

In his speech at Chicago’s Grant Park on Election Night, the president-elect called it a rejection of “the myth of their generation’s apathy.”

Eric Greenberg, who studies this group, known as Echo Boomers, Generation Y or Millennials, goes as far as calling it a “changing of the guard, a new political epoch, a youth movement.”

“They believe the solution starts with themselves, and we just saw it play out in Technicolor on Election Night,” says Greenberg, author of “Generation We: How Millennial Youth Are Taking Over America and Changing Our World Forever.”

That attitude, he and others say, was an ideal match for a candidate whose catch phrase is “Yes We Can.”

AP exit polls show people under 30 comprised 18 percent of those who voted in Tuesday’s election, essentially the same as their 17 percent share in 2000 and 2004. But Obama’s 66-31 advantage over John McCain among voters age 18-29 was easily the biggest margin for a Democrat in presidential exit polls going back to 1972.

As a racially and ethnically diverse generation, young people had an appreciation for a candidate of mixed race that their elders sometimes did not.

Suddenly, it was young voters who were leading their elders, not following, as they have tended to do.

“Obama,” Van Ostern says, “has forged a path that countless young Americans will follow.”