How will you be able to determine that? Blacks vote for democrats like 96% of the time.
Just my thoughts based on how i see it playing out. If there are blacks who are on the fence about voting, i think voting for her is attractive. They want to be represented; just like we saw a lot of moderate blacks vote for Obama. She has a horrible track record, the only reason she's on the ticket is because she's a black female. She's a two for one in order to sway people who are struggling to vote for Trump. Hell even my own mother told me a few weeks ago she's the best thing to happen to the Democrats since Hillary.
I asked why? She said because females need to be in positions of power. Has nothing to do with her politics; a lot of liberals vote based on emotion, not based on logic. That's my problem with most of them. In my opinion, everything needs to be founded by logic and reason, just because you are emotional about something doesn't make it good for you.
