What is government for, and who says so?

Aquinas taught that the purpose of law is to make men good as far as possible, in conformity with natural law.

Kant teaches that the purpose of law is to afford men the maximum possible liberty consistent with the like liberty for all.

Liberals traditionally (and nowadays libertarians along with many conservatives) have maintained that the primary – in some cases, the only – political good, the only legitimate aim of the state, is liberty.

Hobbes teaches the first purpose of government is to impose peace and end the war of all against all that confronts mankind in a state of nature, thus guaranteeing the physical safety of its subjects.

Locke and his epigones teach that the purpose of the state is to guarantee to each the safe enjoyment of his natural rights and, specifically, the rights to life, liberty, and (for Locke) property or (for Jefferson, a crucial difference) the pursuit of happiness.

The US Constitution supposes such legitimate aims of government – anyway, the federal government – as are to be found in the preamble, Section 8 of Article I, or elsewhere. 

Numerous more recent political thinkers have held the general welfare, economic equality, or the common good to be legitimate, even overriding political goods.

Others have said the same about self-rule through some form of direct democracy or popular, representative government. 

But all such doctrines and in fact every political philosophy is exposed as fantasy by the teaching of amoralism.

Leaving behind plenty of room for comment on the actual, as opposed to legitimate, aims of the Leviathan. 

Think of Marx, Bakunin, and the view that the state is essentially and only a tool enabling exploitation by a ruling class. 

And other assessments, perhaps equally dark, though less narrow, less rigid, and less implicitly despairing or utopian.