The paper introduces the Post-Sustainability Trilemma (PST) and argues that it provides a novel description of current environmental politics which is alternative to the one provided by the narrative of sustainability. According to PST, the three policy goals of (i) economic growth, (ii) participation, and (iii) environmental protection cannot be simultaneously attained. Only two of these could. The three possible combinations of PST are then analysed: (i)–(ii) techno business-as-usual; (ii)–(iii) post-growth approaches; (i)–(iii) environmental authoritarianism. Finally, the paper questions whether and under what conditions PST stands. That at least two policy goals could be obtained is a debatable, and debated, claim. In this sense, PST might be considered an over-optimistic framework to organise environmental politics. These considerations open up a space to argue that, given the set of policy possibilities offered by PST, more radical conclusions – such as radical degrowth, radical decentralisation or, even, uncivilisation – might follow.