Digital systems are becoming increasingly complex and distributed, integrating cloud infrastructures, large software supply chains, cyber-physical systems, artificial intelligence components and heterogeneous infrastructures operated by multiple actors. Traditional security mechanisms focus primarily on protecting secrets, isolating execution, or controlling access. While these mechanisms remain essential, they do not address a growing architectural challenge: governing critical security operations in systems whose infrastructure cannot be fully trusted or audited. This paper introduces the concept of Trusted Security Governance Platforms, a new class of security infrastructure designed to provide verifiable mediation and governance of sensitive operations involving critical assets. These platforms extend the role historically played by Hardware Security Modules (HSMs) by transforming traditional trust anchors into programmable trust anchors capable of enforcing security policies across complex digital ecosystems. More broadly, we argue that such platforms enable the emergence of structural trust architectures in which reusable programmable trust foundations support governed security services across increasingly large and heterogeneous digital ecosystems. We argue that Trusted Security Governance Platforms represent a natural evolution of trusted computing architectures and may become a foundational component of future high-assurance digital infrastructures.