2) The other problem is more personal. Even if there may be fewer abortions voting for a Democrat, I still have to, in my conscience, justify voting for someone who thinks that the practice is legally acceptable. I am supporting someone who is pro-baby killer (in my view). Even if that makes logical sense, I just couldn't do it on a moral level.
If you think abortion is murder, and you are willing to concede that it's entirely possible that Democrats will enact policies that lower the rate of abortions, then you're not helping anybody by insisting on a rigid purity lens.
Besides which, I have a very difficult time believing that almost any anti-choice people truly equate abortion with murder. Some do, but those who do are either behind bars for murdering abortion doctors or lauding those who are. Because killing a mass murderer is totally justifiable, right?