System‑Layer Failure: A Structural Analysis of the Under‑16 Social‑Media Ban in Australia, Canada, and the United States

System‑Layer Failure: A Structural Analysis of the Under‑16 Social‑Media Ban in Australia, Canada, and the United States examines the rapid emergence of under‑16 social‑media bans across multiple jurisdictions and demonstrates that these policies are not child‑protection interventions but structural outputs of institutional incapacity. Using the SignalRupture governance‑layer framework, the paper identifies two core primitives—the Downward Regulation Principle and the Visibility Constraint—to explain why institutions redirect regulatory pressure from opaque, transnational platform infrastructures to the only visible and enforceable layer: children. Drawing on early evidence from Australia’s implementation, the paper shows that the ban collapses on contact with reality due to architectural incompatibility, platform noncompliance, and adaptive user behavior. It then maps the Policy Misrecognition Pipeline, a structural sequence through which system‑level harms are progressively reframed into individual‑level enforcement targets. The analysis extends to Canada’s replication of Australia’s model and the United States’ construction of pre‑implementation scaffolding through state‑level legislation and judicial framing. The paper situates the ban within a broader governance‑layer pattern: when institutions lose access to system‑layer levers, they substitute visibility for causality, producing symbolic enforcement, judicial overload, and cross‑jurisdictional policy contagion.