Continuing the discussion of the major practical challenges which implementation of the proposals for a supranational World Authority would face, this chapter considers the question of how all of the world’s states might be persuaded to come on board with the initiative. To attempt to bring states aboard by military force would be a contradiction of the whole project, and so it must occur by the persuasive force of rational argument. The world’s smaller states would perhaps have little difficulty in joining up because of the manner in which their sovereignty is often in practice limited by the machinations of great powers in their zones of influence and because they have little or no supremacist baggage. But larger states, in particular “great” powers with imperialist tendencies, would probably refuse outright to be involved. Hence, we propose that those states who are willing should proceed with the supranationalist initiative without those “great” powers which do not wish to participate (the EU+ASEAN could be a powerful starting point); and once up and running and capable of financial and energy self-sufficiency, these states should erect an iron curtain, a total blockade of all interactions of any kind with those who do not wish to participate. This may not be ideal in certain respects, but we argue that once the use of military force to attain the supranational order is renounced (much as did the EU in 1950) to rely on rational persuasion, there is little other realistic alternative. The chapter closes by noting that our proposals are not some panacea that will cure today’s manifold problems (the polycrisis of Edgar Morin) but is rather a necessary political institutional innovation to addressing the polycrisis.