That’s my understanding too. The key is that this process of baselining takes time, which you don’t have either when there’s half a dozen 50MT Russian warheads

That’s my understanding too. The key is that this process of baselining takes time, which you don’t have either when there’s half a dozen 50MT Russian warheads coming your way (TFA refers to the missile sites being a nuclear “sponge”, i.e. forcing the Russians to launch on them and use warheads that could be targeted against cities instead) or when you want to destroy them in a preemptive first strike before they can be launched.