Robert Goodin in Philosophy and Public Affairs:
Democracy might be characterized, semicircularly, as a matter of “groups of people making collective decisions in a democratic way.” I employ that circularity deliberately to bracket off the part of the formula that I do not want to focus upon for present purposes.
Of course, what it is to “make collective decisions in a democratic way” is precisely the part of the formula that traditionally preoccupies democratic theorists. Is that a matter of expressing opinions or of aggregating votes or of deliberating together? (And if “all three,” then combined how and in what proportions?) Insofar as it is a matter of aggregating votes, according to what rules? (Simple majority rule or something else?) Insofar as it is a matter of elections, what makes them free and fair? (How are campaigns to be conducted, electors apportioned to districts, and so on?) Are there any substantive constraints on what democracies may or must do? (Respect human rights, for example.) Such questions constitute the warp and the woof of democratic theory.
All that leaves to one side, however, the prior question of who exactly it is that is to be making those decisions in that democratic way. How do we specify the group making those decisions? That is what I shall call the problem of “constituting the demos.”1
Writing in 1970, the preeminent democratic theorist of the previous generation complained, “Strange as it may seem . . . , how to decide who legitimately make up ‘the people’ and hence are entitled to govern themselves . . . is a problem almost totally neglected by all the great political philosophers who write about democracy.”