The American experiment has produced elections where there is no practical effect of choosing one candidate or the other because they both serve their own group of special interests. It is merely a choice between the special interests who prefer the color red or those who prefer the color blue.
If they don't serve the same group of special interests, then it would follow that who won would have a practical effect.
Frankly, overall your claim seems ridiculous. Obama and John McCain are for tackling the energy crisis in different ways. Obama wants to make the tax code less regressive, and McCain wants to make it more regressive (
Our Regressive Income Tax | Middle Class Impact). Obama has a more diplomatic stance on foreign policy, whereas McCain has more confrontational one. Among other health care proposals, Obama wants to let people buy the same health care federal employees presently receive, whereas McCain wants to give people a $5000 health care tax credit. Etc, etc.
Just because neither of them is a libertarian or socialist, doesn't mean that there are not significant differences between them.