In the debate over hypersonic missiles vs layered defence, two developments changed the tone this year: credible Navy–MDA testing of terminal defence upgrades and a renewed push to fund the glide-phase kill chain in space and at sea. The question is no longer whether a defender can touch a hypersonic threat at all; it is whether sensors, command-and-control, and interceptors can deliver repeatable effects at a sustainable cost. Recent events—from “Stellar Banshee” testing to U.S.–Japan Glide Phase Interceptor (GPI) cooperation—show a layered route forward, but also expose a harsh cost curve that favours the attacker [1][2][3][4].