With the traitorous bastard as the Republican nominee, the Democrats could nominate a ham sandwich and win. It's a foregone conclusion.
At this point attacking McCain and going as far as advocating that the Republican Party dump him ONLY serves to improve Obamas chances to get elected.
There is no way (nor need) to improve the Dem nominee's chance of election as long as the Pubbie nominee is a back-stabbing RINO.
Securing a 'mulligan' at the convention only serves to provide a slim chance of winning.