International Law and Cyberspace: What Does State Silence Say? (2025)

As cyberspace has become a rising priority along humanitarian, economic, political, and military lines, States have come to regularly participate in myriad aspects of its global governance. Amidst the verbal and physical State acts that come with this participation, however, significant State silence remains. Even more significantly, the legal salience of this silence has itself been met with silence. This chapter offers an inaugural assessment of how silences implicate international law-making in cyberspace through a descriptive and normative lens.

First, as a descriptive matter, we differentiate the absence of rhetoric about silence in international law from its factual existence in various contexts. We introduce three cases – (i) Internet governance, (ii) secret/covert State sponsored cyber-operations; and (iii) unilateral statements by States about international law in cyberspace – where State silences exist and offer tentative thoughts on their legal salience. These cases lead us to conclude that, although the cyber context may have little to say about State silence and international law at present, that inattention itself suggests conditions that may implicate whether and when silences garner legal salience: (a) clarity about relevant legal rules; (b) transparency about relevant State behavior; (c) capability in terms of understanding the underlying claims or conduct; and (d) susceptibility of circumstances to rapid change.

Second, extant ambiguity about State silence in cyberspace provides grounds for a normative claim: beyond thinking of silence only as “reactive” to some acts or speech by others, international law would benefit from acknowledging other manifestations of State silence – which we label catalysing and partial – in cyberspace. Catalysing silence involves the absence of verbal and/or physical acts of States – whether reactive or not – that empower alternative regulatory forms (e.g., voluntary non-binding norms) or authorities (e.g., non-State actor voices about international law). Partial silence involves instances where there is some verbal/physical State response to claims or conduct but that reaction remains silent on all relevant international law implications. We ask whether and when partial silences might signal acceptance, non-acceptance, or opposition. Taken together, we aim to start a conversation about the capacities and constraints of silence to construct international law in cyberspace while offering additional frames for assessing State silence’s salience to international law overall.

Duncan B. Hollis (Contact Author)

Barrie Sander