A reader writes in regards to Obama's performance:
The late Alan Baron used to have the "15 and 50% rule" for cities. If a city was at least 50% black, it would almost certainly have a black mayor (Detroit, DC, Atlanta, etc.). If a city was less than 15% black, it MIGHT have a black mayor because a small minority wouldn't create all that much tension. (LA [where Tom Bradley won five elections from 1973 onward] and Seattle fit this mold).
On the other hand, if a city was between 16 and 49% black, they probably would NOT have a black mayor. The reasons were simple: at say, 30% black, the community was big to stir up a backlash, but not strong enough to win a majority. New York is the classic example of this at 30% black. David Dinkins has been their first and only black mayor. [Similarly, Harold Washington, who died 20 years ago, was Chicago's first and last black mayor.]
Obama is winning the white voters in states where no one is scared of blacks (North Dakota!). He's also winning the Deep South states where black Democrats outnumber white Democrats. But in the big states where blacks are mixed in competition with Catholic labor voters, Asians and Hispanics, he's struggling.
Alan Baron would have predicted this!