Government always tries to protect one from his or her neighbors; however, a sovereign of one country is not necessarily sovereign over the people of another country. The need for people to defend themselves against potentially thousands of non-neighbors necessitates a national defense mechanism. Militaries are created to deal with the highly complex task of confronting large numbers of enemies. As one of the most important role government always provide security and enforce Law to us for our well-being. The instruments that are used for this purpose are Police, the management of Identity documents etc. Governments works for increasing people's survival potentials, and in that same purpose, governments became involved in manipulating and managing regional economies. One of a great many examples would be Wang Mang's attempt to reform the currency in favor of the peasants and poor in ancient China.