This study presents a semantic-enunciatif study of modality, through the explicitation of underlying operations to construction of modal markers of statements. For description and explanation of these markers, two corpora of enunciated of opinion articles published in Brazilian and Portuguese periodicals had been selected. One of them explains operations and the other one, analysis modal passage. Adopted boarding theoretician-methodological was Predicatifs and Enunciatifs Operations Theory, of the French Antoine Culioli. For this theoretical picture, modality (or modal value of a statement) corresponds to the result of abstract localization of the predicatif relation (or proposal) in relation to the subject parameter of articulation, identified for S0. This operation characterizes the point of view of S0 about what it enunciates, assuming the constructed knowledge or being distant of it, depending on the modal value attributed. From this postulate, and with observed regularities, we consider, in this inquiry, an approach that characterizes, in an ampler and generalized way, enunciated constructed modal values in opinion articles. It proves, as results, that opinion article is modalized in both kinds of journalism - Brazilian and Portuguese - very similarly, and modal passage, constructed in analyzed articles, can be identified in two macro plans: validated and available. In validated domain, we have enunciated in scope of evidenced, assumed and/or appreciated, for S0, author of article. This plan corresponds to a judgment of value through which S0 evidences existence of a state of things. In available domain, enunciates are constructed in which S0 considers a solution for the problem, it means, a new perspective for current state, presented in validated domain. In this plan can be seen not an state of things but the desire of construction of a state of things.