What is the difference between the two anti-missile systems in the United States, TMD and NMD (every time I see this, I always think wrongly, maybe I am evil...)

TMD is the English abbreviation of regional (theater) missile defense system; NMD is the English abbreviation of national missile defense system. (Check the full English name yourself). Both are large-scale anti-missile defense systems, consisting of multiple points, lines, and arrays. TMD is mainly applicable to overseas military bases and confrontation frontier areas; NMD is only deployed in the United States. Generally speaking, TMD has a wider deployment range than NMD, but NMD is designed to defend the United States, which means that it is more closely connected and unified than the various parts of TMD. Because it acts on a target! The Aegis system is just a defense system for surface ships (I have always wondered why it is not called "Sea King Shield"...). It is characterized by fast response, strong anti-interference, and the ability to track multiple targets both above and below the water and prioritize those with the greatest threat. to prioritize destruction. Please check the detailed principles yourself. I basically don’t even understand the general idea. I only know that the radar detects the target - the main system analyzes and issues instructions - the fire control system controls the weapons to respond - anti-missile, anti-ship, anti-submarine and other weapons perform their duties to attack or intercept the target - the system performs preliminary guidance and The final guidance ensures the striking effect.