Like we told you. Missile defense shields were envisioned by people not bright enough to know how easy they would be to breach.
While America worked on a system to stop ICBMs from 1965, meanwhile the Russians created nuclear cruise missiles traveling at several times the speed of sound. You could no more hit these missiles with another missile than you can fire a dime from Idaho at Jupiter and hit a painted target on one of it's moons the size of a 50 cent piece. It will be a century before any computer could possibly react that quickly or that accurately.
The plan in the 1960's was to detonate one nuclear weapon to stop another. That was a pretty good plan as far as ABM systems go and nobody has ever improved on it. The problem is nowadays that in order to stop an incoming cruise missile flying at Mach 7, you'd have to detonate a dozen nukes in front of it very close to the ground, which would kind of defeat the entire purpose of trying to stop it.
So once again, as Vault-Co predicted, we return to the foremost conclusion of them all concerning the survival of people in the modern world.
THERE IS NO SUBSTITUTE FOR A CIVIL DEFENSE PROGRAM. THERE NEVER WAS. THERE NEVER WILL BE. ANY NATION WITHOUT A CIVIL DEFENSE PROGRAM IS JUST PLAIN STUPID.