Imagine an international instrument that does not merely oblige contracting parties to confer rights on copyright holders (permitting only optional, narrowly circumscribed, exceptions) but also mandates limitations. Imagine, too, that such an instrument requires parties to permit use of material that has been taken from existing works and incorporated in a later work, irrespective of the purpose of so doing, but only on the condition that the use is in accordance with fair practice. Imagine that the mandatory limitation allows the reuse of transformed versions of works, including parodies, and even the whole of a protected work. Imagine, indeed, a regime of global, mandatory, fair use.