I hate these pollsters hedging their bets. Regardless of the outcome the Harris pollsters get to say "See? We got it right!"
That's all this is. They want to get picked up by more outlets in 2008 based on their "accurate polling" this time around. So they make the numbers say whatever you want them to say.
I'd rather have the additional information they present, and to see what goes into their assumptions in analyzing the results, than for them to just come out and declare one set of numbers as being "correct". At least this way we can see the possible range of outcomes. The fact is no one really knows how best to define likely voter this year. Why should a pollster try to pretend that know any better?