Any government that wants to be taken seriously needs teeth. This chapter sketches a global security system in which national governments will still play a key role, but in which they have also worked together to create stable mechanisms of collective security. Since it is impossible to coerce nuclear-armed Great Powers through direct military action, the new global security system will need an especially robust regime of economic sanctions. If a Great Power transgresses international laws in egregious ways, such sanctions would aim to persuade the leaders of that nation that the costs of continued violations greatly exceed the benefits. In extreme cases, such sanctions could also aim to destabilize a transgressor nation’s economy so severely that its citizens would be impelled to bring about regime change from within. If such a global security system were in place for many decades, successfully keeping the peace, then incremental steps toward reductions in standing armies could be gradually undertaken. The resulting “peace dividend” could be used to further reduce global economic disparities, and to help fund the technologies for mitigating climate change.