Biden sealed his #2 spot on the ticket this cycle when he deliberately snarked Bam-Bam on the gay marriage issue.
If Obama dumps Biden, he infuriates the gays. They won’t vote for Romney, but they’ll stay home.
Biden is also one of the few persons in the White House with strong ties to organized labor. They are very upset about Charlotte.
I’ve never seen a state of affairs with a cast of characters that even approach this. There might be one here and there but this whole cast is a mess.