In the present paper I approach Judith Butler’s theoretical contributions concerning the concept of citizenship. Butler has not developed a systematic theory of citizenship. Nevertheless, I affirm that this theory can be reconstructed on the basis of her social ontology and her account of performative contradiction. In order to prove this statement, I undertake firstly the above mentioned reconstruction. Secondly I derive from the latter an original way of thinking the exercise of citizenship in terms of performative contradiction. Thirdly I assess the convenience of this point of view in order to understand radical citizen claims at present. As an example, I analyze the Argentinian demand of legalization of abortion. Insofar as this demand includes in some cases medicamentous abortion, it expresses the exercise of a right that women do not yet possess legally.