An anonymous reader who wishes to remain anonymous due to current position in the GOP writes:
My line of argument, which I would heartily encourage anyone else to adopt, is that for conservatives in certain states -- WA, OR, CA, HI, IL, ME, VT, NY, MA, RI, CT, NJ, DE, MD -- a vote for McCain is truly a wasted vote, and there should be no hesitation in voting third party. Yes, the election is still close at this point, but it's not -- thank God -- a national popular election. In these bluest of states, our electoral votes are a foregone conclusion, and helping McCain get from 39.87463% to 39.87465% in any such state certainly doesn't change the outcome, but passes up the best opportunity we will have for the next four years to send a message for change to the GOP leadership. If the Constitution Party, for example, can pull the same 7% in the general that they did in some races in the WA primary, we will have sent that message very successfully. In battleground states, conservatives may easily be forgiven for feeling conflicted; in states where the battle is already over, the choice is clear.
Of course, some party hacks will just use such data to scold conservatives as "purists" and throwing the election to the Democrats, and lay the usual guilt trip. But if they get their heads out of the sand, the data would be difficult to argue with.