Relax, there's already a plan in place. We can just use Trumps travel ban as a starting point. First of all we need to keep these American Terrorist in their own states while the extreme vetting is taking place. We can then extreme vet people that have religious connections to these known American Terrorist (Christianity for example) we can also extreme vet States where these American Terrorist are known to often come from...That alone has cut your 300 million people down to a more manageable number...Now we just need to implement it, then fine tweak it and we might save A LOT of Americans...Unless that's too much work for you, if that's the case and Americans aren't worth the effort, then nevermind...#MAGA