'Numerical Parity'.

The article reports that Raytheon and Lockheed Martin are taking very different design approaches as they compete to address the Missile Defense Agency's growing concerns about tracking and destroying multiple targets, even decoys, lofted by ballistic missiles aimed at the U.S. Intelligence officials are concerned that decoy technologies developed by the former Soviet Union and Russia have spread to would-be adversaries or could be duplicated by countries building up arsenals of ballistic missiles.