Should We Talk With "Unpersuadables"?

How to speak to voters who at this stage of the election--less than two weeks to go--still ardently support John McCain is a topic that has been on my mind quite a bit, lately. I think of them as 'the unpersuadables.'  No matter what we may say to them, they are not voting for Obama.  Period.  So, what do we say to them?