What was the change in the white vote for Miami-Dade County?
It depends on what you'd consider white in Miami. Miami Dade is majority white if you include white Hispanics and that white vote swung towards Obama. The Non Hispanic white vote is a lot smaller and honestly I don't know how it might have swung.
Now, let's look at the national trend and the Florida trend, overall whites voted more for Romney, blacks stayed about the same, and hispanics voted more for Obama. If you look at Dade County, you can see that it swung to Obama more so than last time. Considering the miniscule white population, only one in five in the county are white, and considering that about half of the county is hispanic white, and the fact that people in the county are kind of segregated (http://demographics.coopercenter.org/DotMap/index.html) then you can imagine the (more liberal) white vote going to the right, while all other groups trended towards the Democrats.
That map is kind of hard to tell, I wasn't able to zoom in close enough on my end. However, I could see some of the white areas swinging towards Obama. I'm assuming Miami Beach is part of Dade County. If so, that area seems to be getting a lot whiter and higher end. I bet these white voters are voting just like Northeasterners now.
