The powers of the provincial governments are circumscribed by the national constitution, which limits them to certain listed "functional areas". In some areas the provincial governments' powers are concurrent with those of the national government, while in other areas the provincial governments have exclusive powers. The constitution prescribes a principle of "co-operative government" whereby the various layers of government must co-ordinate their actions and legislation; it also lays down a series of rules for resolving conflicts between national and provincial legislation.