We know that law is a major enabler of the human activities that cause climate change, biodiversity destruction, and related ecosocial crises. We also turn to the law to regulate, mitigate and attempt to transform these unsustainable human activities and systems. Yet, third, these regulatory regimes are often ‘recaptured’ or ‘overridden’ in turn by the very anthropogenic processes causing the crises, as Joseph Stiglitz puts it. The resulting vicious cycles constitute the global trilemma of the twenty first century that is rapidly rendering the living earth uninhabitable for humans, in rapidly unequal ways, and for thousands of other species. Integral, nonviolent, sustainable democratic constitutionalism is one, modest, experimental, trial and error, response to this trilemma. In the lecture, Professor Tully will set out basic features of this response and discuss its strengths and weaknesses with the audience.