"If you break the poll down by demographics, then there is no way to account for McCain's lead going down. McCain has the same or more support from every group as he had when he was ahead. The polls are oversampling liberals. "
Translated, they increased the Dem intensity factor and decreased the Repub factor. ie. they must be interviwing MORE Demos than Reps. Get it?
I have known for a long time that many pollsters do that.
If Walls St can cook the book, do you not think SOME pollsters might also "Cook the book"?
When looking at the internal data & details , McCain is also leading in every region other than the northeast among these national polls.
The non political polls such as (non-partisan) Rasmussen and Battleground Polls have them TIED in latest poll.