Federalism or devolution involves the organization of public power so that government, on at least two levels, is responsive and accountable to the people that it serves. More than 25 countries around the world operate as a federation of some kind. Many more devolve power in other ways, either across the country or in particular regions with special autonomy. This Constitutional INSIGHT explains why any change from a centralized to a federal or devolved system is a significant one. It also outlines some of the challenges that arise in the context of such change, and suggests options that might be available to meet them.