The ASTM Additive Manufacturing Center of Excellence, in collaboration with the UK Ministry of Defence's TAMPA program, has released the 'Strategic Guide for Certification of Additive Manufacturing Parts for Defense Applications,' now available for free download. This guide provides a common, part-criticality-based certification approach for defense organizations, manufacturers, and suppliers across air, land, and sea domains. It establishes a four-level part classification system (A to D), where certification evidence requirements are determined by safety criticality, and offers two pathways: process certification and testing certification. Evidence requirements cover raw material control, equipment and process qualification, product verification, and non-destructive testing. Designed to be nation-neutral and technology-neutral, the guide is applicable to supply chains outside the UK as well as those of AUKUS and NATO allies, and represents a pre-standardization effort. This guide is a key step in addressing inconsistent cross-border certification standards, providing a unified reference framework for scaling additive manufacturing deployment in defense sectors.