[NormsRevenge]

This image from video provided by Comedy Central shows Sen. Joe Biden, D-Del, interviewed by 'The Daily Show' host Jon Stewart, right, in New York City Wednesday night, Jan. 31, 2007. Biden parried with Stewart over his controversial description of Democratic rival Sen. Barack Obama as 'clean' and said he had called the senator to explain. 'I bet you did,' Stewart quipped. 'I also spoke to Jesse (Jackson) and Al Sharpton,' Biden said. 'And Michael Jordan and anybody you could get your hands on. The Jackson Five,' Stewart said, interrupting. (AP Photo/Comedy Central)

[NormsRevenge]

Democratic presidential hopefuls, Senate Foreign Relations Committee Chairman Sen. Joseph Biden, D-Del., left, and Sen. Barack Obama, D-Ill., talk on Capitol Hill in Washington, Wednesday, Jan. 31, 2007 during the committee's hearing on Iraq. Later Wednesday night Biden parried with Comedy Central's 'The Daily Show' host Jon Stewart over his controversial description of Democratic rival Sen. Barack Obama as 'clean' and said he had called the senator to explain. (AP Photo/Susan Walsh)