Both the video and a transcript of the discussion are available at the above link.
Bill Moyers gets perspective on the role of impeachment in American political life from Constitutional scholar Bruce Fein, who wrote the first article of impeachment against President Bill Clinton, and THE NATION's John Nichols, author of THE GENIUS OF IMPEACHMENT.
"The founding fathers expected an executive who tried to overreach and expected the executive would be hampered and curtailed by the legislative branch... They [Congress] have basically renounced — walked away from their responsibility to oversee and check." — Bruce Fein"On January 20th, 2009, if George Bush and Dick Cheney are not appropriately held to account this Administration will hand off a toolbox with more powers than any President has ever had, more powers than the founders could have imagined. And that box may be handed to Hillary Clinton or it may be handed to Mitt Romney or Barack Obama or someone else. But whoever gets it, one of the things we know about power is that people don't give away the tools." — John Nichols
Related: My earlier post on The Case for Impeachment.
UPDATE: DCup has an excellent elaboration.