Missile defense is one of those technologies that has the potential to dramatically destabilize certain aspects of warfare. Back in the 1980s, when Ronald Reagan began his fixation on “Star Wars” ballistic missile defense, wiser heads pointed out that: a) it’s really hard b) if it did work, it would mean the US was setting itself up to “win” a nuclear war.
That dynamic has somewhat played itself out over Israel: US-provided theater anti-missile technologies appear to work semi-well against old cold-war era rockets. Wiser heads point out, naturally, that anti-missile technologies simply drive a shift to cruise missiles, which cannot be intercepted on a simple ballistic trajectory. In fact, it means that re-invention of drone missiles (basically, the V-1, V2.0) will be right around the corner. Fixed-wing expanded polyester foam drones built with prosumer electronic control and navigation systems would not be ‘easy’ to make but are within the reach of a dedicated hobbyist. Just add high explosive or an old white phosphorus artillery shell.
But there’s a great deal of money to be made selling these systems because they do work semi-well, and therefore a country can avoid negotiating without fear of incoming high explosive rockets. The other problem with anti-missile missiles is: they’re a missile. You fire one, and now instead of having one missile in your near airspace, you have two. And, as they say, “there is no such thing as friendly fire.”
Anti-missile missiles work by trying to calculate the trajectory of the incoming missile (the control station does that) and sending a missile up to explode in its near path, hopefully shredding it and causing it to explode as well. So, you’re lofting a very fast-moving moderately stupid missile full of high explosive, right over the target, i.e.: your location.
There is going to be an arms-race here, as well. Some clever people may figure out how to make something that looks like a missile incoming, designed to convince the target’s anti-missile missiles to face-punch the target for them.
It’s all fun and games until someone’s life gets blown to shreds.