Unfortunately, the answer is no. In practice, the use of countermeasures would cause the effectiveness rate to plummet, For example, a single ICBM might carry 10 warheads and as many as 200 decoys. These decoys are virtually indistinguishable from the warheads. They will fool both ground and space-based radars and infrared sensors aboard the interceptors. So far, none of the interceptors tested have been able to distinguish decoys from actual warheads.
Decoys are also relatively easy to make and can overwhelm by saturation alone.
For example, to guarantee a 100 percent kill rate, the United States might need 210 interceptors to intercept 10 warheads. As if this were not enough, the warheads could he placed inside inflatable balloons, which would he released and inflated during the coast phase of the re-entry vehicle's trajectory. The balloons, which can be covered by metallic foil making them impervious to both heat and radar detection, may or may not contain a warhead. Other methods of fooling the system include metallic chaff that could be dispensed to blind radars. Some decoys could carry small, active transponders, which send out false echoes, Further confusing the radars.