For the short- and medium-range missiles with which North Korea could look to strike a nearby foe or the 25,000 US troops stationed in South Korea, the US has the Aegis radar-equipped Navy destroyers.
It also has Patriot Advanced Capability-3 interceptors to defend against missiles at their final or terminal stage. These are mostly good at short- and medium-range ballistic missiles.
Finally, the biggest and perhaps the best system is the Terminal High-Altitude Area Defense system. THAAD could cover all of South Korea, including everything up to a Nodong missile, North Korea’s medium-range system.
According to Davenport, it is important to note that the THAAD system will only cover North Korea, but North Korea could evade that by launching a nuke from a submarine from outside of THAAD radar.
She said that North Korea may try to confuse the THAAD system by launching multiple missiles at once or launching decoys.
Experts say that they have every reason to believe Kim Jong Un when he said that he is working toward an intercontinental ballistic missile, and the US defenses suffer from the same uncertainties as systems abroad.
The US protects its western coast from a fixed site in Alaska, where interceptor missiles would theoretically strike an incoming ICBM mid trajectory, while it’s traveling through space.