The U.S. Has No Defense Against a Russian Nuclear Attack. Really
forbes.com
forbes.com
We also have no way of testing the system at scale.
The whitepaper starts "Nuclear war is the only foreseeable threat to America’s survival in this century". I'm confused on how that's foreseeable, while biological warfare, coastal flooding due to global warming, and the emptying of the Ogallala and other aquifers, are not.
That is why most research is geared towards having a "kill vehicle" destroy the warheads (as opposed to something like space based lasers, or railgun, etc).
An antiballistic-missle that kind-of-sort-of can destroy warheads with kinetic energy, is actually quite effective if you strap a powerful nuke onto it.
The general population would never accept having a bunch of nukes pointed to explode over their own country, but it is probably easier to ask forgiveness after defending against a nuclear strike than to ask permission before hand.
How do you test it?
The GMD has a 50% failure rate during hit-to-kill intercept tests. That's with a single target, time to prepare, and several decades of funding.
To implement the full shield the author wants systems for boost, coast, and reentry phases. This includes "hundreds of spacecraft ... to assure a handful are within range of boosting missiles at the time of launch." There's no one word of how to test system integration.
Going back to physics, one of the scenarios in the whitepaper is to defend the US against an attack with 10 nukes, designed to take down the power grid. Won't setting off our own defensive nukes give the same result? The same magazine has a article on how woefully unprepared the US is for an EMP attack, at http://www.forbes.com/sites/peterdetwiler/2014/07/31/protect... . Frankly, it makes Forbes sound like it's still lingering in the Cold War.
And just how do you hide away enough nuclear tipped missile interceptors to be useful, for the decades until they might used, without having to ask for some pretty big permission? There's a good chance that the operators will have to practice setting off nukes over their own houses, or that of friends and family. Not good for morale.
A missile defence program is actually handy, not necessarily for the actual protective power it can provide, but for the rhetorical power it can provide for a President's adviser when the next Curtis Lemay demands that we attack them before then can attack us.