The Introduction recalls why the progressive transformation of European economic integration law into European community and constitutional law remains the most successful example for using regional law and jurisprudence for promoting also global community law. Section I explains why authoritarian and neoliberal rejection of “transnational constitutionalism” undermines collective protection of global public goods demanded by citizens. Section II describes how Europe’s multilevel democratic constitutionalism continues to enable the European Union to exercise leadership for UN and WTO legal reforms such as compulsory WTO adjudication and international emission trading systems aimed at mitigating climate change by reducing carbon emissions. Section III uses the examples of competing internet regulations in China, Europe and the USA, and of international criminal law (like the arrest warrant of the International Criminal Court against Russian President Putin), for explaining the limits of constitutional and institutional restraints on UN and WTO governance
