Mind-boggling complexity: The challenge is to design an intelligent system that finds and destroys targets in a nuclear battlefield

In a simulation exercise Like the one done by researcher Christopher T. Cunningham at Lawrence Livermore National Laboratory, it seems almost easy. A salvo of 1400 intercontinental ballistic missiles is fired on the screen, confronting a strategic defense system. Ninety percent of the missiles are picked off by laser battle stations in the boost phase, before they deploy their warheads and penetration aids. The second defensive tier destroys 90 percent of the remaining 10 percent of the missiles; the third and final tier is 90 percent effective against the rest of those that leak through. Overall effectiveness of the system: 99.9 percent.