Asymmetric federalism or asymmetrical federalism is found in a federation 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 dissatisfactions that arise when one or two constituent units feel significantly different needs from the others, as the result of an ethnic, linguistic or cultural difference.
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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").