This draft aims at opening a discussion about the adequacy of non-stratal, non-derivational models of phonology, such as Declarative Phonology, to give appropriate accounts of any kind of phonological variation of morphemes. Refuting the assumption that all variants of one single morpheme correspond to a unique underlying form consecutively respecified through ordered adjustments of phonological shape, Declarative Phonology seems able to integrate explanations of both suppletive and non-suppletive alternation. A rough application of this model to suppletive alternation in Portuguese will be sketched out.