Who should have a right to participate in a polity’s decision-making? Although the answers to this ‘boundary problem’ in democratic theory remain controversial, it is widely believed that the enfranchisement of tourists and children is unacceptable. Yet, the two most prominent inclusion principles in the literature – Robert Goodin’s ‘all (possibly) affected interests’-principle and the ‘all subjected to law’-principle – both enfranchise those groups. Unsurprisingly, democratic theorists have therefore offered several reasons for nonetheless exempting tourists and children from the franchise. (...) In this paper, I argue that their attempts fail. None of the proposed rationales can do the job without having unacceptable implications for the voting rights of other groups. I then develop a new specification of the affected interests-view, one that avoids such problems. According to my life plan-principle, a person is entitled to participate in a polity’s decision-making if and only if its decisions will actually affect her autonomously chosen life plans, or prevent her from developing or revising plans of that kind. I show that this principle straightforwardly avoids enfranchising tourists and children, and thus improves upon its two prominent rivals. The paper ends by considering and rejecting two objections to my new principle. (shrink)