" . . . their bias should be the same in both polls."
You're such an innocent. If they're willing to bias their polls, in other words, to make them deliberately misleading, then that means they're willing to lie. If one is willing to lie, doesn't it make sense then to use those lies to ACCOMPLISH something? It's much more effective to play with the results in such a way that public opinion is manipulated. By overstating the Bush lead after the Republican convention, and making it disappear altogether now, they can create the impression that the momentum has completely shifted away from Bush and towards Kerry. The big MO, you know. If you're a stocktrader in real life, you should know the drill-- the analysts hype a stock beyond all rational basis, then all bail at once. Some people make a killing, but most people get screwed, and neither the overly rosy view nor the overly gloomy view was ever a fair representation of reality.
The moral of the story is, never trust a liar. Even if they're telling you what you want to hear. Liars lie.
Such an "innocent"? GEEEEZ! Every,,,and I mean EVERY poll,,,regardless of WHO is taking it--has a BIAS!!!!!