Traditional debates on legal theory have devoted a great deal of attention to the question of the determinacy of legal rules. With the aid of social sciences and linguistics, this article suggests a way out of the ‘determinate–indeterminate’ dichotomy that has dominated the academic debate on the topic so far. Instead, a dynamic approach is proposed, in which rules are deemed to undergo processes of political ‘de-determination’ and ‘redetermination’. To illustrate this, the article uses the example of Article 125 of the Treaty on the Functioning of the European Union, the ‘no bailout’ provision, which played a major role in the management of the Euro-crisis. As will be shown, with the start of the crisis, this provision, whose meaning was once scarcely controversial, became the object of intense interpretative disagreement. As it became politically relevant, the rule also became the site of interpretative competitions, until the intervention of the European Court of Justice disambiguated and redefined its meaning.