 against walter mondale in 84 when he was running for re-election and obama had a bad first debate against mitt romney when he was running for re-election and so this has happened before but the difference with biden is that this subtext of is he up to the job is he too old is he too frail and cognitive problem and so on it's a different subtext than the other two had biden has a different problem and it's a more serious problem because he's not going to get any younger