Rice wouldn't help. Blacks aren't going to vote against Obama because Republicans nominate a black VP I don't believe. Where's the upside?
It may get some dissatisified women voters. It would bring Republican on par with Democrats on the whole "historic election" business. What I think you're forgetting is that I suspect there a lot of whites who want to vote for a black guy and may live in the suburbs and be moderates in general terms. These sort of people could be swayed by a Rice pick. As I said, it'd be a gamble. I'd like it, for sure, but I think the base would react negatively. The negatives would sadly ooutweigh the positives in the end.
I'm not sure it would hurt the base. A lot of that base is a "national defense" or "security" base. She could be an asset with that.
Even on abortion, she's said that GW Bush "has been in exactly the right place."
She also has a more compelling
personal story, in terms of race, than Obama.