Islamic rule

Dear sirs, I have a question regarding the islamic government.    What are the main differences between western rule and islamic rule.    I mean by my question not just the applications of the teachings of islam in the nation. But i mean the differnces in the spirit of HOKM. Ont thing i realize about the western hokm is the concept of the use of RIBA. Example , greenspan can shake the country by modifying interest rates, laying 100s of thouthands of people off work. In islam , the government cannot do that.  My undersanding is islam is 2 sections, one is for the person, i.e salah, zakah..personal conduct...and the other is HOKM, i .e the mulim government... is the muslim government democratic ?my opinition is that it should not...the opinion is between OLI al AMR , i.e the experts and not the whole nation...what does the Pizza guy have to do with the macroeconomic decisions of a nation? Democracy is uded by the west to manufacture concent among the people and does not actually achieve what is it supposed to do, at least in its current model.  It would be ok if you just point me to a book in arabic or english.