Overview:Tonight, astrophysicist and the host of the new PBS show NOVA ScienceNOW, Neil deGrasse Tyson. Jon begins tonight reporting on the short lived presidency of Dick Cheney last Saturday in a segment called "The Cheney Presidency Remembered". While Bush was undergoing a colonoscopy and had to be under anasthesia, Dick Cheney was President for 2 hours. Jon gives a blow by blow account of this event, taking us on a tour of Bush's colon and Cheney's short lived attempt to start another war. Senior Presidential Historian Samantha Kearns Bee talks about the history of this temporary transfer of power in her new book on the Cheney presidency called "Classified, Assified, or Grassified: Nobody Presides for Free, The Cheney Presidency". Jon then reports on the ambassador to Iraq, Ryan Crocker, who talked with the Senate Foreign Relations Committee via a 60" plasma television from Iraq in a continuing show segment called "Mess O' Potomac".