2. He has spent the past 8 years being the "Maverick" and reaching across the aisle. He did this because he thought he would be a media darling and would get cooperation from Democrats this year. Democrats don't break party lines period. When they do, they get exiled ala Joe Lieberman. You can be a Republican and a media darling so long as you are not running. When you run they turn on you like the jackals they are.
3. His Hail Mary move of threatening to suspend the debate and going to Washington backfired.
4. He allowed the economic crisis brought on by Democrat management of Fannie Mae and Freddie Mac to be pinned on him.
5. Towards the end Obama started running as a pseudo-conservative, as the Dems did in 2006.