While we’re on the subject of who’s invited to particiate in presidential debates… I was talking to a right-leaning guy on the Hill yesterday, he noted that the major Democratic candidates have a major, major incentive to keep Mike Gravel and Dennis Kucinich in as long as possible: The presence of the far-left congressman and the rip-snorting way-out-there former senator make all of the others look comparably moderate.

He makes a solid point. Has Barack Obama ever had an easier, cheaper way of looking moderate and presidential than by assuring Gravel that “I’m not going to nuke anybody”? Did Obama ever have an easier time winning over an audience than by telling Kucinich to let him finish?

By making Gravel and Kucinich the designated villains of the debate, Obama and Hillary never have to engage and disagree strongly with a more liberal candidate with an actual base of support – somebody like John Edwards. It’s risk-free verbal sparring.