Why is it not a single Democrat in competitive race is running on Healthcare, but dozens tout vote against it?

Sadcat and Lawgirl, I have a question for you. If this 'reform' is so great, why wasn't it set up to take effect immediately? Why did they set it up so that the majority of it (the parts that will hurt us the most) won't take effect until 2014, which would mean we wouldn't know how bad it really is until (he wishes) he had already won a second term, or until the next president would have to deal with the problems it will cause?