The reasons McCain lost, in top three format, are as follows:
He is a republican. People are sick and tired of these guys. These individuals, mostly white and rich, have ruined the country and rolled back the clock on what little social progress we, as a country and a nation, had achieved. Republicans are basically reactionaries, pro-racism and big business.
Sarah Palin was a bad choice. Sure, she looks like a hot aunt, but just as such, there is no where to go with her, and she can't be trusted. She lacks substance as a VP choice and was a pontential liability to her country, she doesn't even know major supreme court decisions; I know two.
McCain is a war "hero" (oxy-MORON alert).. In this day in age, we don't want to think about Iraq, much less Vietnam. Please. I think we've had enough wars, thanks, but stop by next time you want to unload a couple trillion dollars of debt on us. Oh, you all ready have? Get out.