It's better than most polls. If we treat each group as 1/3rd of the electorate, then the 18-point Kerry lead among independents would give Kerry a 6-point lead. Bush's 86% support among Republicans vs. Kerry's 79% support among Dems would lead to a net gain of 4% for Bush (that's a 7-point difference in margin among 2/3rds of the electorate, that's over 4 points in Bush's direction).
So without any weighting of Dems over Republicans, his poll should show a 2-point Kerry lead. It shows a 4-point lead, which indicates a slight imbalance in favor of the Dems. He probably polled about 4% more Dems than Republicans.
Pssst...if these "independents"
truly favor Kerry by 18%, then a
lot of them are LYING about being
indys & are, in reality, DEMS!
Whaddiyuh think about THAT???
Ah, but here's the difference in American politics circa 2004 - we are no longer evenly split between Dems, Reps and Indies.
The total number of swing voters is 8% - 10%. It has shrunk continually over the last decade or so. There are a multitude of cultural (and religious) reasons why this is the case, but the fact is the electorate is more partisan than it has been since the post-Civil War period.
That's why this election is so close, and why Kerry received no post-convention bounce, and why Bush probably won't either. At least 90% of voters (probably more) are committed already, and nothing will change their minds.