Jiří Levý’s article Translation as a decision process (1967), one of the earliest contributions to the topic of decision-making in translation, anticipates a model that was proposed more than two decades later: Optimality Theory. This linguistic theory offers a framework for resolving conflicts in grammar by replacing absolute rules with violable constraints whose interaction leads to the selection of an acceptable output. The philosophy of Optimality Theory can be successfully applied to the process of translatorial decision-making, which consists in proposing a set of candidates and selecting the best one by virtue of constraints imposed by the translation strategy adopted. The article shows how such a constraint-based approach can be used in legal translation. A tentative set of constraints (Minimum equivalence, Near-equivalence, Literal, Identity, Functional, Transparent, Neutral) is used to evaluate French translation candidates for an English legal term, applying two different strategies: documentary (source-culture oriented) and instrumental (target-culture oriented). The formalism of Optimality Theory, while mimicking real-life decision-making processes, makes the selection of optimal equivalents more transparent and coherent. However, it is only one of the possible tools that legal translators and translation students have at their disposal.