Regional organizations play an important role in shaping domestic and global politics. Regionalism has a long history, both in the history of international political thought as well as in the history of international political practice. The existence of rogue or revisionist states that seek to up-end the status quo can spur regional organizing amongst those states that benefit from the existing order. Critics of the demand-side factors approach suggest that these factors alone cannot fully explain why regional organizations form. They argue that while a slew of regional challenges may lead states to pursue regional organizing, political will and resources are also vital. Regional powers concerned with peacekeeping, for instance, will structure regional organizations to focus more on that objective and less on others they deem to be less pressing. Regional organizations can also play a peace-generating role by punishing deviant behaviour that may increase the likelihood of conflict in the future.