Recently, theorists have sought to justify transnational democracy by means of the all-affected principle, which claims that people have a right to participate in political decision-making that affects them. I argue that this principle is neither logically valid nor feasible as a way of determining the boundaries of democratic communities. First, specifying what it means to be affected is itself a highly political issue, since it must rest on some disputable theory of interests; and the principle does not solve the problem of how to legitimately constitute the demos, since such acts, too, are decisions which affect people. Furthermore, applying the principle comes at too high a cost: either political boundaries must be redrawn for each issue at stake or we must ensure that democratic politics only has consequences within an enclosed community and that it affects its members equally. Secondly, I discuss three possible replacements for the all-affected principle: (a) applying the all-affected principle to second-order rules, not to decisions; (b) drawing boundaries so as to maximise everyone's autonomy; (c) including everyone who is subject to the law. I conclude by exploring whether (c) would support transnational democracy to the extent that a global legal order is emerging.