You also have to remember, though, that the Empire is controlled by a Sith and his apprentice. Whatever the Emperor wants, the Emperor gets. We have seen in the movies that if you fail, or even happen to disagree with the way things are run or whatever, you'll die. This type of government is essentially a dictatorship, kind of like the one that used to exist in Iraq. In a dictatorship, the dictator, emperor, king, or whatever they want to be called, will do pretty much anything they want to do and will kill those who even might have thought about thinking about opposing him/her. Maybe, when the Empire was first declared, it could have been considered a constitutional monarchy, with a senate or parliament and a King in charge, but Palpatine got rid of the senate in ANH, so it is more like a dictatorship. Once Palpatine and the second Death Star were killed, another dictator rose to take place of the Emperor and continued in his legacy (ex: Isard, Thrawn, Pellaeon, etc.).