This is helpful:
The Department of Defense will deploy a Terminal High Altitude Area Defense System (THAAD) ballistic missile defense system to Guam in the coming weeks as a precautionary move to strengthen our regional defense posture against the North Korean regional ballistic missile threat.
Of course, it will take weeks to emplace them. It would be nice to have the time before being attacked.
And this decision comes after many days of North Korean threats.
So can we always count on weeks of warning by missile-armed enemies? Is it wise to count on making an appointment for a mutually agreed upon day to let the missiles fly?