The subject is surely the most worthy curiosity of any the wit of man can possibly devise. And who knows, if this controversy were fixed by the universal consent of the wise and learned, but, in some future age, an opportunity might be afforded of reducing the theory to practice, either by a dissolution of some old government, or by the combination of men to form a new one, in some distant part of the world?--Hume "Idea of a Perfect Commonwealth"
David Hume's political thought, which councils "reverence to what carries the marks of age," is often and understandably treated as a species of Conservatism.* As Jonathan Israel puts it, "his was a 'moderation' apt only to underpin prevailing usage." (Democratic Enlightenment, 226) In fact, Israel is so keen to contrast Hume with more radical (Spinozistic) approaches, that in drawing on the Natural History of Religion, he reads Hume as a Newtonian providentialist, reinforcing "acquiescence in divine governance of the world." (Israel, 211)
Oddly enough for an author focused on rehabilitating the significance of political ideas in political events, Israel entirely overlooks Hume's essay on a Perfect Commonwealth. According to Hume identifying the "most perfect" "form of government" is the subject of the essay. While the topic is treated as "speculative," it is not belittled--on the contrary, it "surely" is "the most worthy curiosity of any the wit of man can possibly devise." That is, it is most important subject in philosophy. Hume is also explicit in the passage quoted above that he is trying to identify a "system of government" that could be put in practice after, say a revolution or a new founding. So, while Hume is not advocating revolution (that would be sedition), his project is not merely speculative. In fact, rather than setting the ideal in some imaginary place (and he is explicit about the contrast with Utopia and Oceana), he locates it in "Great Britain and Ireland." (Along the way he also insists that the idea that "no large state, such as FRANCE or GREAT BRITAIN, could ever be modelled into a commonwealth," is false.)
Hume's proposal is, in one sense, very democratic in that he advocates annual elections for country representatives (who in turn elect senators and county magistrates). In fact, while there is a monarch (and who has undeniable war-making powers), much else is governed by very frequent elections in order to ensure "sufficient security for liberty, or the redress of grievances." (It also has quite a few far-reaching, anti-corruption measures.) While the proposed franchise is not universal, his property restriction is considered -- in light of the practices and other theories of the day -- not very strict; in fact, it echoes Spinoza's proposed franchise for democracy (which famously excludes women and servants (among others)). Having said that, the elected draw no salary (although those that govern do), so the scheme clearly has a bias toward the wealthy.
Thus, the significance of Hume's scheme becomes clear when we reflect on how his treatment of the House of Lords reveals his anti-feudal-aristocracy-bias:
The number of the upper house ought to be raised to three or four hundred: Their seats not hereditary, but during life. They ought to have the election of their own members; and no commoner should be allowed to refuse a seat that was offered him. By this means the house of Lords would consist entirely of the men of chief credit, abilities, and interest in the nation; and every turbulent leader in the house of Commons might be taken off, and connected by interest with the house of Peers. Such an aristocracy would be an excellent barrier both to the monarchy and against it.
What Hume is proposing here is, in effect, a self-selecting, aristocracy of talent that stabilizes society. This is, indeed, in one sense a form of elitism.** But while it would be misleading to call the idea original (there are echoes of Plato's Philosopher-Kings), it is even more misleading to call this a defense of existing privilege in the eighteenth century sense. Rather, Hume foresees something recognizably modern: the peculiar mix of a (very) wealthy, brainy elite whose rule is legitimized but not threatened by frequent voting. Hume's political thought is still relevant, alas.
* I highly recommend Neil McArthur's David Hume’s Political Theory: Law, Commerce, and the Constitution of Government, which treats Hume as a 'precautionary' conservative.
** See, especially, this maxim: "The lower sort of people and small proprietors are good judges enough of one not very distant from them in rank or habitation; and therefore, in their parochial meetings, will probably chuse the best, or nearly the best representative: But they are wholly unfit for county-meetings, and for electing into the higher offices of the republic. Their ignorance gives the grandees an opportunity of deceiving them."