Principles of constitutional design
After tribal people first began to live in cities and establish nations, many of these functioned according to unwritten customs, while some developed autocratic, even tyrannical monarchs, who ruled by decree, or mere personal whim. Such rule led some thinkers to take the position that what mattered was not the design of governmental institutions and operations, as much as the character of the rulers. This view can be seen in Plato, who called for rule by "philosopher-kings." Later writers, such as Aristotle, Cicero and Plutarch, would examine designs for government from a legal and historical standpoint. The Renaissance brought a series of political philosophers who wrote implied criticisms of the practices of monarchs and sought to identify principles of constitutional design that would be likely to yield more effective and just governance from their viewpoints. This began with revival of the Roman law of nations concept and its application to the relations among nations, and they sought to establish customary "laws of war and peace" to ameliorate wars and make them less likely. This led to considerations of what authority monarchs or other officials have and don't have, from where that authority derives, and the remedies for the abuse of such authority. A seminal juncture in this line of discourse arose in England from the Civil War, the Cromwellian Protectorate, the writings of Thomas Hobbes, Samuel Rutherford, the Levellers, John Milton, and James Harrin ton, leading to the debate between Robert Filmer, arguing for the divine right of monarchs, on the one side, and on the other, Henry Neville, James Tyrrell, Algernon Sidney, and John Locke. What arose from the latter was a concept of government being erected on the foundations of first, a state of nature governed by natural laws, then a state of society, established by a social contract or compact, which bring underlying natural or social laws, before governments are formally established on them as foundations. Along the way several writers examined how the design of government was important, even if the government were headed by a monarch. They also classified various historical examples of governmental designs, typically into democracies, aristocracies, or monarchies, and considered how just and effective each tended to be and why, and how the advantages of each might be obtained by combining elements of each into a more complex design that balanced competing tendencies. Some, such as Montesquieu, also examined how the functions of government, such as legislative, executive, and judicial, might appropriately be separated into branches. The prevailing theme among these writers was that the design of constitutions is not completely arbitrary or a matter of taste. They generally held that there are underlying principles of design that constrain all constitutions for every polity or organization. Each built on the ideas of those before concerning what those principles might be.