I'd argue that the consensus built by the current crop of Democrats is more of a monotone than a considered debate. The same holds true for the GOP. The Heritage Foundation didn't achieve its successes without first building a set of core beliefs and a dogma.
So what have we gotten? A Healthcare Reform Bill which is more concerned about the Healthcare industry and the idea of "profits are privatized, losses are socialized." I have no idea what the new state-run insurance companies are going to charge per month, nor do I know if I'll qualify for the tax code hand outs that are designed to ease the pain from paying for healthcare. I guess we'll see in 2014. 2014. Why did we wait so long to implement change? That's another question the Administration failed to answer, and no one was willing to ask. Previously GW Bush, a "conservative," made the largest "free healthcare" expansion since LBJ created Medicare.
Back to GOP vs DNK. Obama was elected partly because "he got it." Candidate Obama could send a text message and update his Twitter account. He also supported Net Neutrality. That was big four years ago. Now we have a Comcast/Verizon/ATT/ETC driven broadband policy and a lukewarm Net Neutrality policy. President Obama bowed down to corporate interests just as GW Bush did when he was President. There are more examples, like the on-going budget crisis and the impending Super Committee's upcoming Final Failure 2 release. I think I've made my point. It's getting hard to identify what each party and politician supports. Both parties are so close in action, yet so far apart in dogma I get a 1K mile stare whenever I encounter someone who clings to dogma and ignores action.
The original poster's question stands: How can we choose, when you can't identify real and meaningful differences between the candidates and the parties?"