You should be able to discuss, with specificity, systems and programs including the Integrated Battle Command System, Patriot and PAC-3 MSE, the Lower Tier Air and Missile Defense Sensor, Sentinel A4, THAAD and AN/TPY-2, Indirect Fire Protection Capability Increment 2, Forward Area Air Defense C2, Maneuver SHORAD and the Marine Air Defense Integrated System, Aegis Baseline and Aegis BMD with the SM-3 and SM-6 families, Command and Control Battle Management and Communications, and the Ground-based Midcourse Defense system with the Next Generation Interceptor. By the time a requirement is written, the architecture it assumes has usually already been chosen, and the useful work happened eighteen months before that in requirements documents, analyses of alternatives, and conversations with program offices and operational units about what is actually limiting them.