These types of contingencies point precisely to the reason why the U.S. nuclear triad exists. Here's What You Need To Remember: The Air Force is now moving along with efforts to build as many as 400 new, high-tech, more capable ICBMs intended to bring U.S. nuclear weapons capability into a new era. Imagine if America’s land-based intercontinental ballistic missile (ICBM) launch silos were destroyed, its nuclear-armed ballistic missile submarines have been found and neutralized, and its nuclear bombers cannot get over enemy airspace. All the while, during this nightmare, the continental United States itself is suffering a catastrophic nuclear weapons attack. This scenario is highly unlikely, but not impossible.