He meditates on this graph:
The Clinton Firewall -- In These Times: The Race Chasm may sound like a conventional discussion of the black-white divide, but it is one of the least-discussed geographic, demographic and political dynamics driving the contest between Clinton and Obama... you are left with 33 elections that best represent how the black-white split has impacted the campaign... when you chart Obama's margin of victory or defeat against the percentage of African-Americans living in that state, a striking U trend emerges. That precipitous dip in Obama's performance in states with a big-but-not-huge African-American population is the Race Chasm--and that chasm is no coincidence.
On the left of the graph, among the states with the smallest black population, Obama has destroyed Clinton. With the candidates differing little on issues, this trend is likely due, in part, to the fact that black-white racial politics are all but non-existent in nearly totally white states.... On the right of the graph among the states with the largest black populations, Obama has also crushed Clinton.... "in the Democratic primary the black vote is so huge [in these states], it can overwhelm the white vote," says Thomas Schaller, a political science professor at the University of Maryland--Baltimore. That black vote has gone primarily to Obama, helping him win these states by big margins.
It is in the chasm where Clinton has consistently defeated Obama. These are geographically diverse states from Ohio to Oklahoma to Massachusetts where racial politics is very much a part of the political culture, but where the black vote is too small to offset a white vote racially motivated by the Clinton campaign's coded messages and tactics. The chasm exists in the cluster of states whose population is above 6 percent and below 17 percent black, and Clinton has won most of them by beating Obama handily among white working-class voters...