There is a tension between democracy and sustainable development: While democracies are jurisdictionally limited by national borders and are committed to the current interests of voters, the concept of sustainable development transcends these spatial and temporal boundaries. Regarding the intertemporal dimension of sustainability, the urgent issue of intergenerational justice is philosophically well-addressed. But what is still missing is an elaborated conceptual and argumentative link both to political science and to real-world democratic politics. Adapting concepts of democratic theory, this paper establishes the conceptual foundation for analysing how to consider the interests of future generations in our present-day democratic institutions.

First, it is laid out what is meant by future generations, and why it is so difficult to take their interests into account today. Second, the so-called non-identity problem is discussed and rejected. Third, it is demonstrated that future generations will be causally and legally affected by the political decisions of today, and therefore, that ignoring the respective policy impacts violates the democratic all-affected principle. Fourth, with this it is shown that the issue of future generations is an issue of deficient political representation. Therefore, the concept of proxy representation is being developed to encompass not yet present constituents such as future generations. Based on this, a list of real-world “proxy representatives” of future generations is presented.