1. Reduction in size = reduction in RCS
2. PENAIDS = more complex threat cloud to sift through and discriminate
3. Chaff countermeasures
Unfortunately, their is a limit to employing countermeasures in this domain in practice [not in the wild imagination(s) of cook-the-books experts though].
Sensor architecture is evolving to a great degree on the whole. Radar systems are becoming increasingly powerful and smart in the matters of identifying objects [of interest] and distinguishing them from each other. US have developed and fielded radar systems which can easily identify and discriminate objects [about the size of a golf ball] from over 1000 KM away; they also have chaff discrimination capabilities (velocity measurement being one of the tricks). Sophisticated midcourse discrimination techniques such as X-Band high-resolution imaging, micro-motion sensing and multi-spectrum IR imaging techniques have emerged, which can be "sensor fused" to produce an incredibly rich picture of the threat cloud in the exo- atmospheric conditions. This "sensor fused" can be swiftly fed to an advanced interceptor (EKV) in order to make sure that it will engage the right target. There is also the option to destroy multiple objects in a threat cloud via SALVO engagement (current) or MOKV engagement (near future). Otherwise, take your chances in
terminal phase (multi-layered defenses).
It would eventually come down to the number of warheads vs. number of interceptors. If you have sufficient firepower to exhaust the defenses of an opponent, you will eventually score. However, a war is a very dynamic environment in which so many variables are at play. Chances are that you won't get the opportunity to attack the same target repeatedly because the enemy would be striking at your positions as well.
Huge mistake.
Special forces raids - might work in certain situations.
Big wallet - best option.
[build a bigger and better war-machine]
