Currently, Avatar is being trashed in conservative circles because it portrays good, decent white humans as villains trying to steal the land of a non-white primitive people.
Unfortunately for them, most other critics seem to like it. This means Big Hollywood will adopt the strategy they used for movies like The Blind Side where they trash it for being politically incorrect then, when it becomes a huge hit, they backtrack and claim it's actually a win for conservative values.
Therefore, after they see that they failed not only to kill Avatar but to even blunt its box office, expect to see several Big Hollywood articles saying that it's a conservative screed that vindicates the Iraq War and that Sam Worthington's wheelchair bound character who enters an alien body clearly represents George W. Bush.
Another possibility is that it will make $300 million and they'll claim that they prevented it from making $400 million but I'm sticking with my first guess.