In the 70's there were some out-there proposals to build silos into the southern slopes of the Rocky Mountains, to make life harder for inbound nukes from Russia. There were also proposals to use nukes to throw sand into the path of arriving warheads. Anyone know more about this?https://twitter.com/dex_eve/status/1410323395170881537 …
The terminal phase ones pretty much have to, because intercepting at Mach 20 is too hard. The idea behind the sand one was to detonate a buried nuke to throw debris into the path of arriving warheads. "Now you have two problems"