Name recognition is powerful, so is appearance and he uses his goofy court room psychology when working the crowds. But they are stupid enough to fall for it. People are generally more comfortable with the evil they know than an unknown, furthermore he can somewhat use the position and some of the assets of his office to help him get reelected. Obama has a huge symbolic advantage because he's half black, from a broken family, raised in Indonesia, urban, associated with the new England elite. All things I would run away from, but in the US these have become things that work for the candidate. Symbolism is reality for most who don't even know a candidates education, experience or track record in voting etc. They vote on a “gut feeling” and Obama maintains these high popularity levels because of the “symbolism” behind him.
Near 1/3 of all Americans have become dependent or entitled to some form of government redistributive program. Most of these see the Dems and Obama as the party of choice. Gays as many blacks do feel he delivered for them. When people say that Obama has failed, you're usually talking about those that have jobs or businesses, not the ones that saw one extension after another and are suckling on welfare or unemployment for over 102 weeks. Those that don't even need to show that they are looking for work anymore to get benefits intended to bridge one over between jobs. Gays are happy because they now have access to social security, medicare and medicaid, that's what it really has all been about, money. They can now openly serve in the armed forces and here too you have a group that is not at all unhappy with Obama’s performance. Tree huggers are generally happy with him, as are baby mamma's that are also looking for free hand outs and focus on "what's in it for me," i.e. free health care.
Obama IMHO will win, for all the wrong reasons, but nonetheless, he will win. The Republicans and conservatives feel pumped up right now, sort of like after watching a really good war movie, but that feeling fades quickly.
Go see 2016 and report back.