After seeing Episode III, I don't know how anyone can say that it's not all about Bush. I mean really. "He controls the Senate and the courts."
With or without the political overtones, it's a great movie. Go see it. I won't give away any plot points that weren't already known, but we already knew most of the major events that have to happen before Episode IV:
* Anakin Skywalker turns to the Dark Side and becomes Darth Vader.
* The Republic becomes the Empire, and Chancellor Palpatine becomes Emperor.
* Padme Amidala gives birth to twins, Luke and Leia.
* Anakin and Palpatine become physically disfigured.
* Obi-Wan and Yoda go into hiding.
* The following characters appear in the original trilogy (and therefore don't die in Episode III, so we know how the major lightsaber battles turn out): Obi-Wan, Yoda, Anakin/Vader, Palpatine, C3PO, R2D2.
* The following characters do not appear in the original trilogy (hmmm): Padme, Count Dooku, Mace Windu, all of the other Jedi.
So it would seem that there is no room for suspense in Episode III. But they pull it off anyway! The ending (really the middle) is particularly effective.