A couple days ago I was listening to the radio and caught a brief snippet of a review about SWe3 - RotS. It was talking about how wonderfully the Cannes Film Festival in France applauded the movie for supposed Anti-American Sentiments. George Lucas' response was also interesting but not because he straight out said: "yeah, it's Anti-Bush" but because he was so vague about it. The reviewer read it as being politically oriented towards Anti-Bush so that he pleases the French and keeps the Americans happy and viewing his film. This may or may not be true, but the there are only a few instances that it seems to be Anti-American in so far as anything against absolutism could be considered evil.
WARNING: this is safe to read, I will not give away any of the plot. BUT, if you plan on taking children under the age of 10, please see the movie first. It contains a few emotionally charged scenes that can be disturbing to children!
The problem with trying to parallel RotS to being an Anti-American Film is that the political matrix of the Republic is not the same as it is in the USA. The Republic is Parliamentary and without an Executive Branch. The Jedi can be likened to the Judicial side, but no more. The issue with Palpatine/Darth Sidius is that there is a true power grab going on in which he becomes the executive branch in a government not created for one. The USA was created with an Executive Branch whose power is checked by the Judicial and Legislative branches. So the likeness can only be drawn from the choice of words.
The main link is a close approximation of what Bush said about the war on Terror in 2001: "You are either with us or against us in the fight against terror." But even then the paraphrase is offset by the usual "Sith are absolutists" talk (what Lucas could make of Christians is a mystery - tongue in cheek). Course, the issues in the film and the issue with the war on terror are worlds apart. The film is essentially dealing with an internal split (more akin to the South deciding it wants to secede) as opposed to an external enemy bent on your destruction (such as Germany and Japan in WWII or the terrorists who think of us as the Big Satan). Different dynamics.
The film itself is a definite improvement over the first two episodes, but suffers similar issues with acting being poor. The visual effects are impressive and the underlying story is worthwhile, but, like in the first two, the acting can get bothersome. While Lucas may have a certain vision and knack for story telling, his stories are better directed by other people (see The Empire Strikes Back). I wonder how well the first Star Wars would have done had Harrison Ford not been accidentally cast as Han Solo; I suspect the film would have been popular, but only as an underground film. He formed a catalyst in the first three films that was lacking in the last three.
RotS is worth seeing, not for the acting, but in seeing how the troubled Anakin falls and the fate of Luke and Leia's mother spins out. The space battles are impressive. A couple of new enemies are impressive. Anakin's hideous transformation is terrifying and satisfactory. Leaving the theatre and thinking: "wow, great film but the acting was still below par" was a very strange feeling.



Comments
Democracy vs. Totalitarianism
I did not see anything anti-bush in this film. Which I am pretty sure was your point as well. The only thing political is by ideal, that absolute power corrupts absolutely. Those in power who arrived their illigitimately will do everything in their power to further establish and protect their power base. It is the Sith way.
As for my opinion of the film, I have written up a quick review.
Yep...
...but when you read the reviews or hear the news, it is bound to come up. I mention it mainly because some people may not want to see the film if it is blatantly anti-Bush. Cannes is really at fault for that impression.