The objectives of this paper are 1) to review the concept of ‘Polity’ in Aristotle’s Politics and Nicomachean Ethics, 2) to discuss arguments for and against Aristotle’s concept of polity, and 3) to examine and discuss the relevance of Aristotle’s concept of polity in accordance with the intentions of the 2007 Constitution of the Kingdom of Thailand. The author finds that polity – democracy in its best form, distinguishes rulers based on their perfect virtues. The word ‘mean’ is used to describe the basic tool to form up polity, as well for an individual’s moral standard in finding a meeting ground between two extremes. Therefore, the goal of Aristotle’s concept of ‘polity’ is not only to accomplish the best form of government, but also to achieve the form of the best life. Hence, this paper discusses the arguments for and against Aristotle’s concept of polity, as well as its opposite, in the context of the development of the Greek ‘city-state’ that resulted from the implemented morals, ethics and developmental standards, all of which are still nowadays universally relevant. Opposition to and support for Aristotle’s polity, rulers and their characteristics, was argued for and against in the behaviour of absolute sovereigns and totalitarianism which are forms of regimes which do not act within the best interests of the state’s citizens, but in fact act only for the rulers themselves. This paper finds that the concept of polity means the rule by the many for common interest; therefore, ‘polity’ is against totalitarianism in any form, upholds the participation of the people, and to ensure that any bad government can be deposed and replaced peacefully. Then, after discussion of the relevance of Aristotle’s concept of ‘Polity,’ the intentions of the 2007 Constitution of the Kingdom of Thailand are examined. The author finds that almost all Aristotle’s key characteristics of polity are relevant to the intentions underpinning the 2007 Constitution of the Kingdom of Thailand. The author also arrives at the conclusion that there is no constitution that is completely perfect and that each constitution must be tailored by an appropriate balancing of the citizens and their country’s context.