NORAD has moved back into the Cheyenne Mountain Complex, after a decade above ground at Peterson AFB, Colorado. (Now that Stargate SG-1 has moved out.) A mile of granite shields against both blast and electromagnetic pulse (EMP).
A high altitude nuclear blast could disrupt unshielded electronics–the power grid, air traffic control centers, your car and cell phone–over a huge radius. Hardening electronics is simple and relatively cheap, but few systems beyond strategic military ones are protected.
North American Aerospace Defense Command takes the threat of rogue nuclear attack seriously; why doesn’t Washington? In 2008 the Congressional EMP Commission drafted an executive order to protect the national infrastructure. It’s unsigned.
A 1983 made-for-TV movie, The Day After, featured the paralyzing impact of EMP. We’ve know about it since the 1950s, but nothing’s been done. It’s easier and cheaper to design EMP hardening into circuitry than to add it later. (Radio Frequency shielding is common, but EMP shielding is different.)
Possession of nuclear weapons by Iran and North Korea threatens the United States, not just their immediate neighbors.