Sometimes in polling two wrongs make a right.
I think that today's new Research 2000/Daily Kos Poll showing Kay Hagan leading by four and Barack Obama up by two in North Carolina is right on the money.
How they got there, however, does not match up with reality. In 2004 the electorate in North Carolina was about 79% white, 18.5% black, and 2.5% other. Although I'm sure it will be more colorful this year, Research 2000's projection of 69% white, 24% black, and 7% other is not realistic. 74% of registered voters in North Carolina are white, 21% are black, and 5% are other races. Typically non-white people here vote at a much lower rate than whites- if minority voters simply match the proportion of registered voters they comprise that would be a huge movement in and of itself, but they're not going to turn out at such a disproportionately high level that whites get pushed down to 69% of the electorate when they're 74% of registered voters.
(Before someone puts the demographics from the first few days of early voting in the comments to try to show me I'm wrong, keep in mind that over 40% of early voters during the primary were black but the election day voters were so disproportionately white that it pushed the total final African American share of the vote down to 34%.)
So if the Research 2000 poll significantly over samples minority voters, why aren't its numbers overly friendly to Obama and Hagan?
Because they find Obama getting just 27% of the white vote. This was the same problem with the R2K poll of North Carolina last month, which showed McCain with a 17 point lead. Simply put, Obama has zero chance of winning the state if he really only gets that percentage from white voters. He needs 35-36% at a bare minimum, and we've found him as high as 38% there the last few weeks.
I believe this poll is wrong in that it projects minorities to make up far too large a segment of the electorate, and it is wrong in that it gives Obama far too little of the white vote. But those two errors offset to produce topline numbers that are very reasonable.