Modern radars should largely negate theater decoys, and improved internetting of sensors, battle management, and command and control have multiplied combined effectiveness. However, aggressors could challenge such theater defenses with advanced technologies. The earliest could be chemical and biological weapons, which must be intercepted at higher altitudes to avoid effective dispersal multiple munitions.
Nuclear weapons require very low leakage defenses.
Theoretically, they could be produced by compounding the kill probabilities of current concepts, but it is likely that they will require more direct counters. In the Gulf War, missiles breaking up during reentry accidentally generated stressing maneuvers. In the future, aggressors will intentionally program their weapons to generate such maneuvers. Interceptors might be able to overcome them with better accuracy, range, and guidance, but as yet the penalties are not known, other than through computer simulations. The technologies for release are readily available or adaptable.