It’s not necessarily anything like a “Bradley effect” (which probably did not apply in that case either - the CA polling was terrible in that campaign).
It’s (1) fake poll recipes that have over-sampled Dems, and (2) pollsters now have to try to be accurate in the final days before Nov. 4, and (3) more people are paying attention and thinking about what the radical socialist Obama really represents.
Propagating the idea that Obama’s problems have anything to do with race is simply a left-wing talking point.
There is a 3rd item, which I would call the “Quasi-Bradley Effect.”
It doesn’t have to do necessarily with race, but rather with the fact that there are a FEW people out of a hundred, maybe 2 or 3, who will pull their punches because they do not want the poller to know who they are voting for.
Normally the 2 sides would tend to cancel each other out on this, but this year is a very unique atmosphere. The Obama advertising tsunami combined with the unprecedented level of press bias have made it abundantly, oppressively, clear that Obama is the cool, with-it guy and only very stupid people would vote for McCain and the Idiot Woman.
There are people who are psychological “people-pleasers,” who will balk at stating their true intentions because it is their life-habit to never offend “the-powers-that-be.” And this year “the powers-that-be” are working overtime to ridicule the very concept of supporting McCain.
If ONE person in 100 responds this way, it means one percentage point LESS for Obama and 1 MORE for McCain. If two respond this way, it changes the race by a net 4%, etc.