Politics in Sci-Fi/Fantasy

Whether you write these genres or just love to read them, what role does politics play in science fiction and fantasy worlds? I participated in an online panel to discuss just that. Who does it well? Who does it less than well? (The Star Wars prequels, anyone?) Is it always necessary to have politics in a sci-fi or fantasy book? Find out what I and other SFF writers have to say about it, and feel free to let me know your thoughts on it, too.