A vote is not an oath of loyalty or fidelity. Think about that. It is a pragmatic choice. If a vote is being taken to remove my leg or my head, I am not going to sit it out.
We have already failed and been handed the lemon. Now we must try to make lemonaide as best we can.
In order to make lemonade that's fit to drink you need to add sweetener. Where is that sweetener going to come from to make the lemon (McCain)palatable? His choice for VP? We will see...