The Guardians in Plato’s Ideal city serve as the protectors and leaders. They are the soldiers and the rulers. In fact, Plato divides the Guardians into two groups: the Rulers and the Auxiliaries. Only the best of the Guardians get to be rulers. Their function is to keep the best interests of the community in mind always. For this reason, they must be educated and tested in youth to insure that they can forgo the temptation to do otherwise.
Plato promotes a division of labor in his city because he thinks that the most efficient way of satisfying the needs of the community is to have everyone practice a particular trade. Each man in his state will be given the job to which he is best suited.
From the point of view of someone who lives in the 21st century, Plato’s city would probably not seem so “ideal”. Plato’s division of labor seems to ignore the personal freedom that we tend to value so highly today. This is to say nothing of the profound censorship that he imposes in the education of the Guardians. Judging from his account of the Myth of the Metals, people in his city do not seem to choose their own lot in life. Plato seems to firmly believe that a person should perform only one function.
While it never ceases to amaze me how so many of Plato’s ideas, that are well over 2000 years old, are still relevant today, I believe that Plato’s Ideal city would go over like a lead balloon in today’s society. People tend to value personal freedom and personal expression too much today to be locked into one function. And certainly, the people of today would not be willing to give up their freedom to choose.