It was a campaign no one will forget, especially the people who worked on it.

One year after the 44th — and first African-American — president of the United States was voted in, the path to that result is retraced today in the new HBO documentary “By the People: The Election of Barack Obama.”

Throughout the candidacy, filmmakers Amy Rice and Alicia Sams had behind-the-scenes access that can only be deemed remarkable.

Among highlights: Early vote solicitors, including an amusingly frustrated 9-year-old, trying to explain who Illinois Sen. Barack Obama was; an Obama cell phone call to congratulate then-rival (and eventual Secretary of State) Hillary Clinton on a win along the primary trail; and the openly emotional reactions of Obama staffers, including then-chief strategist and now-senior adviser David Axelrod, as the returns came in on election night.

Along with such exclusive sequences, the two-hour project incorporates historic moments now familiar to millions, such as Obama's acceptance of the Democratic nomination at Denver's Invesco Field and his victory speech at Chicago's Grant Park.

“I thought they did a great job,” says Axelrod of Rice and Sams' film, which he first saw in rough-cut form. “They poured their hearts into it, and I think they've produced something of lasting value.

“It's moving, particularly because it so heavily chronicles the journey of two of our young campaign staffers, Ronnie Cho and Mike Blake.

“In many ways, they reflected the essence of our campaign. They were very idealistic, they anguished over every setback, and they reveled in every triumph. They represent hundreds of thousands of people across this country who committed themselves to the kind of change they were hoping for. They're the heroes of the story.”

Rice and Sams knew they wouldn't be the only documentary makers pursuing the Obama story; in fact, they learned their competition included two-time Oscar winner Barbara Kopple (“Harlan County U.S.A.”).

“We never felt entirely safe,” Rice claims, “and that only made us fight harder.” Sams notes, “We always wanted more, but as the campaign moved on, it started to dawn on us how good our access was. I was surprised they let us stick around for so long.”

Indeed, Rice says, “The campaign was always growing and changing, and new people were coming onboard. They wouldn't know who we were, so we always had to explain that we were filmmakers, not journalists. We'd have to build new relationships, even though they'd already been told it was OK that we were filming. Also, we weren't the campaign's No. 1 priority. First and foremost for them was winning.”

Axelrod admits he initially opposed granting Rice and Sams such access. “I was one who argued strongly that we shouldn't,” he says, “but over time, they wormed their way into our confidence. That was partially because I learned about Amy Rice's story; when she explained what motivated her to do this project (her brother's death in the terrorist attacks of Sept. 11, 2001), it was very hard to turn them away.