I would try to pitch President2008.com to the 2 main parties... one of them may like to use it as a gimmick... I really so little if any value for the domain itself. The parties may drop 5-10 bills maybe even low $$$$ if a bidding war starts.
Campaign2008.com is another story however in my opinion. As was said before, I think media optins wuld be best. And considering we are talking endusers here, I don't think mid $$$$ is out of the question... but the earlier the better, obviously.
Since it is time specific, I would let the end user parties know that I will be selling by..... date. Otherwise at a certain point you will have driven the car off of the lot. (Depreciation city)
Hope you do well. Remember there may be other elections around the world in the same year... so don't limit yourself in marketing scope.
My 2 cents
DAVID