Asymmetric federalism or asymmetrical federalism is found in a federation or other types of union in which different constituent states possess different powers: one or more of the substates has considerably more autonomy than the other substates, although they have the same constitutional status. This is in contrast to symmetric federalism, where no distinction is made between constituent states. As a result, it is frequently proposed as a solution to the dissatisfaction that arises when one or more constituent units feel significantly different needs from the others, as the result of an ethnic, linguistic or cultural difference. The difference between an asymmetric federation and federacy is indistinct; a federacy is essentially an extreme case of an asymmetric federation, either due to large differences in the level of autonomy, or the rigidity of the constitutional arrangements. An asymmetric federation, however, has to have a federal constitution, and all states in federation have the same formal status ("state"), while in a federacy independent substate has a different status ("autonomous region"). Types Asymmetrical federalism can be divided into two types of agreements or arrangements. The first type resolves differences in legislative powers, representation in central institutions, and rights and obligations that are set in the constitution. This type of asymmetry can be called de jure asymmetry (Brown 2). The second type reflects agreements which come out of national policy, opting out, and (depending on one's definition of the term) bilateral and ad hoc deals with specific provinces, none of which are entrenched in the constitution. This type of asymmetry is known as de facto asymmetry. The Canadian federation uses a combination of these, which make up its asymmetrical character. National examples Canada The Constitution of Canada is broadly symmetric but contains certain specific sections that apply only to certain provinces. In practice, a degree of asymmetry is created as a result of the evolution of the Canadian federal experiment, individual federal-provincial agreements, and judicial interpretation. Asymmetrical federalism has been much discussed as a formula for stability in Canada, meeting the aspirations of French-speaking Quebec for control over its cultural and social life without removing it from the national federation, where it coexists with nine largely English-speaking provinces. The most prominent example of asymmetric federalism in Canada is the constitutional requirement that three Supreme Court justices must come from Quebec. The nine other provinces are each entitled to fair representation in the Supreme Court,