Grim pub quiz

My companion, a friend from my past life as an IT professional who is so normal that he doesn't even have a blog, just asked "So what happens if Obama gets assassinated?"

Given the parallels between his campaign and Bobby Kennedy's, that's been the topic of some discussion around me in the past.  The consensus is that Biden gets the top slot, but of course, by some logic it should be Hillary.  Anyone actually know the answer?