The anticipated emergence of cryptographically relevant quantum computing presents a strategic challenge for national security systems because many existing public-key cryptographic mechanisms depend on mathematical problems that may become vulnerable to sufficiently capable quantum computation. The central difficulty is therefore not limited to selecting a new cryptographic algorithm; it concerns the coordinated migration of complex national infrastructures, institutional processes, data repositories, software platforms, and interconnected information systems. This research and review article develops a policy-oriented roadmap for post-quantum cryptographic migration by synthesizing the supplied literature on quantum-resistant national security planning with evidence concerning technological adoption barriers, data quality, artificial intelligence governance, explainability, bias, implementation complexity, and safety. The analysis conceptualizes migration as a socio-technical transformation rather than a purely cryptographic replacement exercise. A phased framework is proposed consisting of discovery and inventory, risk classification, algorithm and architecture preparation, controlled transition, validation, institutionalization, and continuous assurance. The findings indicate that successful migration requires visibility into cryptographic dependencies, prioritization of mission-critical information, interoperability planning, governance mechanisms, skilled personnel, and continuous validation. The article further argues that lessons from healthcare and AI implementation literature are transferable at the level of governance and technology adoption, although they cannot substitute for cryptographic or quantum-specific technical evidence. The resulting roadmap positions post-quantum migration as a long-term national resilience program requiring executive governance, technical modernization, lifecycle management, and measurable implementation controls.