On Nuclear Countermeasures
A nuke coming to the target (city) by air (ICBMs or bombers) should be
intercepted with shaped-charged explosive(s). This will displace shockwave and
fallout away from the target. Investigate whether small, nuclear, shaped
charges are ideal, as this will guarantee that the incoming warhead is
detonated, and won’t represent a future threat (reassembled by ground crew).
If a nuke-counter-nuke is properly shaped, then the blast and fallout do not
reach the nuke’s target. As for suitcase bombs, just instal Geiger counters on
ingress to nation. Mandatory inspection of heavy lead containers. FBI
honeypots/ traps to counter buying and enriching fissable material acquisition.
23 Nov 16
Apparently nukes not only can be shaped, but usually are already. See quora.com
regarding shaped nuclear charges as a means of propulsion.
Alternatively, an energy shield could be constructed by projecting em radiation,
which can be shaped with extremely powerful magnet(s). However the magnet and
its housing/foundation must be physically strong enough to withstand a nuclear
blast. Or it could block the missile before it detonates; this wouldn’t require
the magnet/base to be anywhere nearly as strong. Thanks Asimov. 23 Nov 16