John Stuart Mill on the need for limited government and political rights to prevent the “king of the vultures” and his “minor harpies” in the government from preying on the people (1859)

Found in The Collected Works of John Stuart Mill, Volume XVIII - Essays on Politics and Society Part I
2009 marked the 150th anniversary of the publication of John Stuart Mill’s On Liberty (1859), one of the key texts in 19th century classical liberal thought. In the second paragraph of this work, Mill states that societies need a system of legal and political rights and constitutional checks and balances in order to prevent the stronger, the "innumerable vultures" and their allied "minor harpies", from oppressing ordinary people in a perpetual struggle between "Liberty and Authority":
To prevent the weaker members of the community from being preyed upon by innumerable vultures, it was needful that there should be an animal of prey stronger than the rest, commissioned to keep them down. But as the king of the vultures would be no less bent upon preying on the flock than any of the minor harpies, it was indispensable to be in a perpetual attitude of defence against his beak and claws. The aim, therefore, of patriots was to set limits to the power which the ruler should be suffered to exercise over the community; and this limitation was what they meant by liberty. It was attempted in two ways. First, by obtaining a recognition of certain immunities, called political liberties or rights, which it was to be regarded as a breach of duty in the ruler to infringe, and which, if he did infringe, specific resistance, or general rebellion, was held to be justifiable. A second, and generally a later expedient, was the establishment of constitutional checks, by which the consent of the community, or of a body of some sort, supposed to represent its interests, was made a necessary condition to some of the more important acts of the governing power.
Once again we have a classical liberal warning us about the problem of “who will guard against the guardians.” In this case it is John Stuart Mill in On Liberty and he uses some very colorful language to describe those who use the government for their own benefit (“vultures”) at the expence of the ordinary people. The vultures have their followers and accomplices, which he calls “harpies” (named after the mythical Greek winged spirits who stole food by snatching it away). The people supposedly set up government in the first place in order to protect themselves from the “vultures” and their “harpies” but inevitably the government is seized by “the king of the harpies” and the cycle of struggle begins again. Mill thought that only constitutional limits on government power, a system of checks and balances, and a vigorous legal and political protection of basic rights could keep the “vultures” at bay. The passage is also significant for his broad perspective on history as an ongoing struggle between “Liberty and Authority” (or “Power” as we call it in this collection of quotations).