>>64399667
Pretty much this. There are really only three different catagories of threats that a ballistic missile shield has to worry about:
1. Rogue launch
Someone in another nation's missile forces fucked up or went insane and launched a singular missile at you. If you stop that missile and any submunitions deployed from it, then disaster is averted and your ballistic missile shield is an outstanding success.
2. Negating deterrence from a minor power.
Some shitty country like best korea or Iran builds a handful of nuclear tipped missiles and points them at your nation, and may potentially shoot them at you if you do something they really don't like. This is extremely expensive to defend against, but is barely within possibility for a wealthy superpower like the US if it put enough resources into doing so (which it arguably hasn't thus far).
3. Another major power launches its entire arsenal at you
Almost everything they shoot those missiles at is going to die, your missile defense is going to do approximately fuck all, and the only possible response is to launch as many of your own missiles as you can before the incoming strikes hit, and then launch any of your surviving warheads afterwards. Both your nation and the attacking nation are functionally destroyed.
Of those three scenarios, the US can maybe stop number 1, and can have a crack at attempting to stop number 2 although I wouldn't rate their chances. Number 3 is functionally impossible with any current or near future interception technology because of how much cheaper it is to simply build more harder to intercept warheads than it is to defend against those warheads, and even number 2 requires massive overmatch between the defender and the attacker for success to be realistic (ala USA vs Iran/NK).
