Six years after the legalization of marijuana for medicinal use, its defenders fear that a change of government will roll back their hard-won rights. Valeria Salech heard her son laugh for the first time on the day she gave him cannabis oil. It was the result of endless bureaucracy. Valeria’s son Emiliano had not been able to obtain allopathic medication to treat refractory epilepsy, a disease that he suffered from since birth and that led…