A confederation (also known as a confederacy or league) is a union of sovereign states, united for purposes of common action often in relation to other states. Usually created by a treaty, confederations of states tend to be established for dealing with critical issues, such as defence, foreign relations, internal trade or currency, with the general government being required to provide support for all its members. Confederalism represents a main form of inter-governmentalism, this being defined as ‘any form of interaction between states which takes place on the basis of sovereign independence'.