You are mistaken, Obama and McCain would split the liberal vote opening the door for a conservative.
I don't believe I am mistaken at all. Republicans scatter, throw fits, and stomp out going 3rd party when they don't agree 100% (or close to) with their candidate. We do this because the issues matter to them that deeply.
Democrats vote are not as issue driven. They like cliches and symbolism. They will vote Democrat no matter what. They lead my the media and party.
Republicans fall for the 3rd party mistake. We will divide up, Democrats wont. A Republican or a Democrat will be in the White House next year, not a 3rd party.