There is not only one form of the Islamic state, but many; and it is for the Muslims of every period to discover the form most suitable to their needs—on the condition, of course, that the form and the institutions they choose are in full agreement with the explicit, unequivocal shariah laws relating to communal life.

Chapter 2: Terminology And Historical Precedent, p 23 - The Principles of State and Government in Islam (1961)