While "Hostis Humanii Generis" is a term with deep historical and philosophical roots, the actual process of declaring someone as such isn't formally codified in modern international law in the same explicit manner as, for example, designating someone as a terrorist or a war criminal. Here's how the concept can relate to current legal practices:
Piracy:
Traditional Application: In the past, piracy was the primary application of this term, where pirates could be captured and tried by any country, not just the one where the act was committed. This reflects the universal jurisdiction principle over piracy.
Modern Legal Framework: Under international law, the United Nations Convention on the Law of the Sea (UNCLOS) allows for universal jurisdiction over piracy, meaning any state can prosecute pirates. This isn't a declaration of being "Hostis Humanii Generis" per se, but it embodies the same spirit.
War Crimes, Genocide, Crimes Against Humanity:
International Criminal Law: Bodies like the International Criminal Court (ICC) or ad hoc tribunals (like those for Yugoslavia or Rwanda) prosecute individuals for war crimes, genocide, or crimes against humanity. While not using the specific term, these crimes are considered offenses against humanity as a whole.
Procedure:
Terrorism:
Philosophical and Symbolic Use:
To formally "declare" someone as an enemy of all mankind in a legal sense today:
In summary, while the term itself isn't part of formal legal procedures, its essence is embodied in the practices of universal jurisdiction for piracy, war crimes, and similar offenses where the act is considered an affront to all humanity.