The Daily Show is an American late-night talk and news satire television program. It airs each Monday through Thursday on Comedy Central. Describing itself as a fake news program, The Daily Show draws its comedy and satire from recent news stories, political figures, media organizations, and often uses self-referential humor as well. The half-hour-long show premiered on July 21, 1996, and was first hosted by Craig Kilborn until December 17, 1998.

In the show's third act, the host conducts an interview with a celebrity guest. Guests come from a wide range of cultural sources, and include actors, musicians, authors, athletes, pundits, policy experts and political figures. During Stewart's tenure, the show's guests tended away from celebrities and more towards non-fiction authors and political pundits, as well as many prominent elected officials. In the show's earlier years it struggled to book high-profile politicians. (In 1999, for an Indecision 2000 segment, Steve Carell struggled to talk his way off Republican candidate John McCain's press overflow bus and onto the Straight Talk Express). However its rise in popularity, particularly following the show's coverage of the 2000 and 2004 elections, made Stewart according to a Rolling Stone (2006) article, "the hot destination for anyone who wants to sell books or seem hip, from presidential candidates to military dictators". Newsweek labeled it "the coolest pit stop on television".  Prominent political guests have included U.S. President Barack Obama, Vice President Joe Biden, former Presidents Jimmy Carter and Bill Clinton, former British Prime Ministers Tony Blair and Gordon Brown, former Pakistani President Pervez Musharraf, Liberian President Ellen Johnson Sirleaf, Bolivian President Evo Morales, Jordanian King Abdullah II, Estonian Prime Minister Taavi Roivas, Canadian Prime Minister Justin Trudeau and former Mexican President Vicente Fox.  The show has played host to former and current members of the Administration and Cabinet as well as members of Congress. Numerous presidential candidates have appeared on the show during their campaigns, including John McCain, John Kerry, Barack Obama and Hillary Clinton.

Answer the following question by taking a quote from the article: Who appeared on the show?
U.S. President Barack Obama,