What Percentage of the White Vote can Obama Take in November?

In 2004 John Kerry lost the presidency by around three million votes. In that race, according to the 2004 CNN exit poll, he got 41% of the white vote. White voters made up 77% of the national electorate. In 2000, Gore carried the popular vote and got 41% of the white vote, again according to the CNN exit poll for 2000. In 2000 white voters made up around 81% of the national electorate. So, in two races, the Democratic candidate was getting around 40 to 41% of the white vote and whites were over three-quarters of the electorate.

This brings us to the 2008 Democratic presidential race. In New Hampshire, Barack Obama got 37% of the total vote. Since New Hampshire is a state that has, according the Census Bureau, a population that is 95.1% white and only 1% African-American, it is a pretty safe bet that almost all of his votes were from white voters. In Iowa 38% of caucus goers chose Obama. Again, like New Hampshire, Iowa is a state that is 93% white, it is again safe to assume that most of his support came from white voters.
Thus, in two races in states that were over 90% white, the best that Obama has done is 38% of the vote.

The issue is whether Obama can do better than that in a national election? Can he get into the 40% of the white vote that both Kerry and Gore got against Bush? Conversely, could he increase the black vote from 11% of the total vote to more like 12 or 13% of the total vote? Given the recent history of two straight presidential defeats where the Democratic candidate only got around 40% of the white vote, the answer to these questions is crucial if Obama is the Democratic nominee.