Obama appeared on the show in October 2012.

Obama appeared on the show in October 2012. Carolyn Kaster/AP

What The Daily Show Has Done for Barack Obama Since 2008

Jon Stewart's audience was the also the president's base.

The first time Barack Obama went on The Daily Show with Jon Stewart as a presidential candidate, in August 2007, he was greeted by audience cheerleaders before the interview even began.

"You rock, Barack!" a chorus of adoring fans called out in unison. Obama let out a delighted laugh, clearly basking in the admiration.

On Tuesday, he'll tape an appearance for the seventh and final time, and pay homage to the youthful, progressive audience: Stewart's viewership and Obama's 2008 base. The Daily Showviewers are the type of people—young and sympathetic to his messages of hope and change—that candidate Obama needed when he was first running against Hillary Clinton. And he got them.

"When you go on The Daily Show, you reach a smart, engaged, youthful audience," Tommy Vietor, a former Obama spokesman, told National Journal—exactly the people who supported the president in 2008.

"One of the things that helped propel him to victory in Iowa among other places was outside support from young people and first-time voters," Vietor, who joined the Obama camp in 2004, added. "And I think Stewart's show was a way to very quickly increase awareness of Sen. Obama—of his candidacy, of his views—with young people."

In the run-up to the 2008 election, Obama went on the show three times: that August 2007 appearance, in April 2008, and October of that year, just one week before Election Day.

Obama never really changed his message when he went on The Daily Show. He continued to hammer his talking points on health care in his 2010 appearance—the "30 million people who are gonna get health insurance as a consequence" of the Affordable Care Act, the law's Patient's Bill of Rights "that makes sure that insurance companies can't drop you when you get sick"—and he will likely use his last taping to sell the Iran deal, reached last week in Vienna, to the millennials tuning in.

That's because the administration views it as just one of a myriad ways to reach a wider swath of people, White House spokesman Eric Schulz told National Journal. It may be sandwiched between briefing the press corps and tweeting about the Cuban Embassy opening or firing off press releases and blogging about criminal-justice reform on whitehouse.gov.

"It is our responsibility to identify the best ways to communicate with the American people," Schultz said. "The Daily Show does have a large audience, and [Stewart] does have impact."

Obama has made something of a tradition of doing the late-night rounds and especially sending off esteemed hosts. He was one of David Letterman's final guests on the The Late Show in May, and he appeared on one of the last Colbert Report shows in December, even taking over host Stephen Colbert's role for part of the segment.

While The Daily Show gave Obama another platform to reach people, his appearances also proved he could pass an important test: the phony detector.

"The appearances with then-Sen. Obama, I think, showed him to be a particularly authentic, honest, likable candidate, and I think that came through in part because Stewart's not easy on these people that come on the show," Vietor said. "He puts them through their paces. He's informed. And he calls bullshit where needed."

That was especially true in 2012.

In that October interview, Stewart jokingly asked how many times a week Vice President Biden shows up "in a wet bathing suit to a meeting." But he also grilled him on Benghazi, Obama's poor performance in the first presidential debate that year, and the administration's continuation of Bush-era "warrantless wiretapping laws" and "government overreaching."

Stewart calling "bullshit," asking about Biden in a wet bathing suit—that allowed for the most important part of Obama's appearances on the show: He was comfortable enough, at least for a six-minute segment, to be himself. And that resonated with the audience more than anything else.

"If you look back at 2012 and the series of interviews the sitting president of the United States gave, probably the toughest interview he had was with Jon Stewart," former White House press secretary Jay Carney said last year. "Probably the most substantive, challenging interview Barack Obama had in the election year was with the anchor of The Daily Show."