Is the self-determination of future generations impeded by lasting constitutions, as Thomas Jefferson suggests? In this article it is not only argued that the opposite is true, but also that the question misses the point. It is demonstrated that the very demand for future generations’ full self-determination is self-contradictory, and that it is impossible to achieve. Applying the all-affected principle to future generations, it is shown that we will always affect them, and that we should employ an attitude of “reflective paternalism” towards them. With the help of institutions reviewed in this article, the interests of future generations could be introduced into today’s political decision-making process. The role of constitutions is to provide the prerequisites for democratic self-determination and potentially also to facilitate the institutional empowerment of future generations.