This article deals with the abuse that can be committed in the name of rights and of the rule of law, not against them. It explains the general characteristics of the concept of abuse from a legal point of view, on the part of the holder of a public power or of a right. Moreover, it addresses the way to identify the abuse itself by the means of legal arguments, and principles. Finally, it shows how resorting to the problem of abuse of power has been used as a tool for recognizing the habeas corpus to detainees in Guantanamo by the Supreme Court of the United States. The summary: 1. The dark side of rights and the concept of abuse; 2. General characteristics of the abuse of a right or a power. 3. Rules, principles and abuse; 4. Rules and the abuse of the Rule of Law; 5. From the Rule of law to the abuse of the power; 6. A Legal Experiment. The Abuse of the Rule of Law at Guantanamo Bay.