Justicia en la toma de decisiones y discrecionalidad estatal.

The paper argues that the theory of the collision of rights, and its accompanying methodologies of interpretation, should be discarded by logical and legal inconsistencies. It offers, in return, an alternative to properly determine the scope of reasonable functioning of rights, and to achieve its harmonization. The emphasis is placed on reasonableness review or proportionality principle, dividing it into six steps or tests. The work takes as axis of the analysis a case on social rights of the Supreme Court of Argentina, where was examined the regulation of mandatory vaccination of children, challenged for the parents. The article made a application exercise of these six tests of reasonableness, presenting concretely how to analyze these legal issues looking for the just answer to the case, which also involved technical aspects and discretionary decisions of the State. [ABSTRACT FROM AUTHOR]