It's been stated elsewhere, but still needs to be shouted far and wide:
1. The poll was of registered, not likely, voters.
2. The poll was weighted in favor of Democrats, whereas the previous post-RNC Convention polls were weighted toward Republicans. Newsweek set us up for this quite a while ago.
3. The poll was conducted only in the Mountain and Pacific Time Zones. In other words, it's trying to portray Left Coast voters as a representative sample of the country at large. L.A., San Francisco, Seattle, and Portland did not decide the last election and they will not decide this one.
4. Newsweek's numbers do not jibe with other polls that also showed Kerry winning the debate, but that also indicated no substantial drop in support for Bush. Nor do they jibe with these CNN/Gallup internals.
In short, the poll is complete B.S. concocted by a desperated partisan media outlet in an attempt to depress conservative voters and, they hope, suppress turnout. DON'T LET THESE LIARS GET TO YOU.
-Dan