The purpose of a debate is to use logic to persuade people to your way of thinking. In reality, emotions and perceptions play a critical role.
Excuses. One I have heard of is the altitude of Denver which possibly is a secondary factor. It might be more realistic to say Obama was fatigued, after all he has a full time job. We will never know all the details of that job, but it is public knowledge that Turkey and Syria were shooting at each other and who knows what other problems the president may have to contend with. Mitt Romney's job is running for president and he can afford to take time out to prepare and be rested.
I had also heard that Obama personally dislikes Romney and was advised to be cool so as not to display his anger.
Some people have been arguing that Obama was giving Romney rope. That can be dangerous as some people will inevitably believe the lies and others won't care because they have locked themselves in.
One report I read suggested that Obama is not confrontational. He would rather conciliate. At the moment the other party seems steadfast and resistant to logic. Definitely Barack has not made as much progress as voters would like, but can they overlook what obstacles have been placed in his way by many of the most vociferous critics. A portion of the public seems upset that a black man with a Muslim father is running the show. Big money resents restrictions that are intended to protect the public interest. The Republicans have decided the best strategy is not to co-operate any more than necessary and more than anything that is the cause of slow progress.
I accept that Romney is an intelligent man and also practical. Like most politicians he realizes he had to jump through a lot of hoops to get to this platform. Pleasing some people inevitably displeases others. Barack has a similar problem, but seems to be more thoughtful and careful. People are always saying politicians lie to get elected and there is a lot of truth to that, although I do not feel politicians really want to do it that way. Nobody wants their taxes to be raised or their services to be cut or their rights to be limited. And there are an awful lot of people that are essentially one issue voters that will ignore their own self interest.
If you actually look at what was said, Romney left himself exposed. He made very bold statements, but avoided critical details. He belittled green energy inaccurately and boasted of his interest in education. Letting Big Bird symbolize PBS may prove to the biggest mistake of all.
Politics is a dirty business. There is a lot of exaggeration, distortion and taking things out of context. As someone said the best disinfectant is sunlight. The world is a dangerous, complicated place and difficult choices will have to be made. The debate was actually very revealing.