It’s full of flaws. Here's What You Need to Remember: It is important for national leaders to recognize that ballistic-missile defenses can only mitigate the risk of a limited nuclear missile strike, not grant a perfectly reliable shield against one. After all, long-range ballistic-missile defenses have never been tested in combat conditions—a state of affairs that even the testers at the Pentagon surely hope will not change any time soon. On the morning of January 31, 2018, an Aegis Ashore missile battery based in Kauai, Hawaii cued onto an approaching intermediate-range ballistic missile (IRBM). The installation launched an SM-3 Block IIA missile to intercept the IRBM at speeds over fifteen times the speed of sound.