(Forms of government, and duties of magistrates. Issues of war and taxation, 8-13)
8. The diversity of forms of government

And certainly it were a very idle occupation for private men to discuss what would be the best form of polity in the place where they live, seeing these deliberations cannot have any influence in determining any public matter. Then the thing itself could not be defined absolutely without rashness, since the nature of the discussion depends on circumstances. And if you compare the different states with each other, without regard to circumstances, it is not easy to determine which of these has the advantage in point of utility; so equal are the terms on which they meet. Monarchy is prone to tyranny. In an aristocracy, again, the tendency is not less to the faction of a few, while in popular ascendancy there is the strongest tendency to sedition. When these three forms of government, of which philosophers treat, are considered in themselves, I, for my part, am far from denying that the form which greatly surpasses the others is aristocracy, either pure or modified by popular government, not indeed in itself, but because it very rarely happens that kings so rule themselves as never to dissent from what is just and right, or are possessed of so much acuteness and prudence as always to see correctly. Owing, therefore, to the vices or defects of men, it is safer and more tolerable when several bear rule, that they may thus mutually assist, instruct, and admonish each other, and should any one be disposed to go too far, the others are censors and masters to curb his excess. This has already been proved by experience, and confirmed also by the authority of the Lord himself, when he established an aristocracy bordering on popular government among the Israelites, keeping them under that as the best form, until he exhibited an image of the Messiah in David. And as I willingly admit that there is no kind of government happier than where liberty is framed with becoming moderation, and duly constituted so as to be durable, so I deem those very happy who are permitted to enjoy that form, and I admit that they do nothing at variance with their duty when they strenuously and constantly labour to preserve and maintain it. Nay, even magistrates ought to do their utmost to prevent the liberty, of which they have been appointed guardians from being impaired, far less violated. If in this they are sluggish or little careful, they are perfidious traitors to their office and their country.

Calvin again disparages the idea of "the consent of the governed." Calvin would apparently disapprove of a form of government which began with the words "We the People." "The People" should not discuss the best form of government. God has placed it out of their hands. George Washington, the "father of his country," disagreed:

A greater drama is now acting on this theater than has heretofore been brought on the American stage, or any other in the world. We exhibit at present the novel and astonishing spectacle of a whole people deliberating calmly on what form of government will be most conducive to their happiness, and deciding with an unexpected degree of unanimity in favor of a system which they conceive calculated to answer the purpose.—To Sir Edward Newenham. Fitzpatrick 30:73. (1788.) 

We agree with Calvin, however, that the results of discussions of the best form of government have not always been profitable. This is evidence of "the depravity of man." But notice that Calvin uses that doctrine to limit the state.

We contend that the only Biblically legitimate form of social order is not 

a monarchy
an aristocracy
a democracy, or
a republic

but a society which might be labeled an "Anarcho-Theocracy." It is a nation "under God," but a nation without the institution of "civil government." It is based on the idea here defended by Calvin: Liberty. John T. McNeill writes:

Calvin is primarily concerned for secure and ordered liberty as opposed to both tyranny and anarchy. "Nothing is more desirable than liberty," he writes of Joseph in Egypt (comm. Gen. 39:2). In the Homilies on I Samuel, he twice calls liberty "an inestimable good." (CR xxxix.544; xxx.185), and again in Comm.Jer.38:25-26. He elsewhere speaks of it as "more than the half of life" (CR xxiv.628). Paul, he says, is careful not to diminish liberty (Comm. I Cor 10:29). God desired the Jews to have more liberty than their neighbors who were ruled by kings, and so gave them liberty to choose judges.

Liberty is good because it is wrong to use force or violence against others. 

Nobody in the modern world agrees with Calvin's pro-state sentiments on this point. Every citizen has a responsibility to study political science and be involved in shaping public policy to some extent. The gap between ruler and ruled has faded away. There is no Biblical principle which should prevent us from eliminating this distinction altogether.