kit wrote:...
You seem think that the people developing and deploying these systems are not perfectly aware of what the effects are. Given that the USSR internally estimated it should be able to defeat 8-12 ICBMs (technically "complex ballistic targets" - which may well be a single warhead+decoys) or up to 40 IRBMs I suspect that they understood how nukes worked. Though they deactivated the exo-atmospheric portion of the system almost 10 years ago without replacement, so who knows.
You may well be right.
Although there is an unhappy history of the widespread deployment of defective weapons. A good example is
https://en.wikipedia.org/wiki/Mark_14_torpedo. Given that from a practical standpoint it is going to be extremely difficult to do an all-up test of such an ABM system I personally wouldn't have a bet-your-capital-city level of confidence that the overall system was going to work -- or even work well enough to matter.
Interestingly, the Russians next-generation ABM system is going to be non-nuclear.
The current Russian A-135 system uses the 53T6 missile that pulls 210Gs! And can maneuver at over 90Gs. Damn.