In this chapter, I address important preliminary challenges to any discussion of deontic principles in ICL. Thoughtful scholars have raised concerns that familiar liberal principles may be entirely out of place in ICL. I will argue: (1) For any system that chooses to punish individuals, deontic principles do matter, and thus they should constrain ICL. (2) This does not necessarily mean replicating formulations of fundamental principles familiar from national systems; instead we can return to our underlying deontic commitments and see what they entail in these new contexts. (3) We can learn from common critiques of liberal accounts, to build a sensitive, humanistic account of deontic principles.

In response to various criticisms of criminal justice and liberal principles, I emphasize the ‘humanity’ of criminal justice. Criminal justice and its restraining principles are sometimes portrayed as abstract, metaphysical, retributive, vengeful, Western, or ideologically unmoored from experience. But criminal law serves pro-social aims. Its constraints are rooted in compassion, empathy, and regard for humanity. An intelligent liberal account considers all facets of human experience, including social context, social roles, and collective endeavours. Principles reflect broadly shared human concerns, and can be refined through human conversation.