If you are like me in feeling utterly disgusted with and unrepresented by both major political parties in this country, and I suspect you are, why do you keep voting for them? No, but seriously.
The argument that everybody endlessly gives, viz. that otherwise the other, worse, party will get elected is, frankly, asinine. It seems like some kind of mass insanity which inevitably results in nothing but the ongoing prosperity of the completely unacceptable status quo. The plain fact is that we will never have a genuine democracy in the U.S. until there are more than two viable parties to choose from, and this fact should in itself be enough to persuade anybody that voting Democrat is a Bad Idea.
I would never, ever vote for a candidate who did not openly and without reservation support same-sex marriage, a woman's right to choose, socialized medicine, funding for social programs, a firm boundary between the government (and education) and religion, massive reduction of our military budget, and environmental well-being over corporate greed -- and neither should any intelligent, responsible, ethical person.
Seriously, people, there needs to be a change in this country, and it needs to happen now. This means you. Don't support the parties whose primary goal is not to rock the boat for fear of losing Ohio.
(For information, here is a comparison of Democrat/Republican positions on a number of key issues compared with the Green Party. Note that I don't necessarily advocate the Greens specifically, but I find this chart instructive.)