Don’t know the range of these systems but it seems to me that places like Vandenberg, Camp Pendleton, Bremerton, and Moffett Field are places to start.
Too bad the Presidio of Monterey was turned into a national park. But the elimination of San Francisco might be beneficial (semi-sarc.)
I just looked up the range of the THAAD system and found this:
“However, it is important to understand that THAAD is an anti-theater ballistic missile system not designed to counter intercontinental ballistic missiles. It is aimed at missiles under a range of 5,500 km and beyond 150 km. It boasts an area protection of 200 km and is capable of multiple launches.”
Thus we are looking at a range arc of 200 kilometers or 120 miles. Thus would need a string of them from southern Alaska down to San Diego. Or around the major cities as was done with the old Nike system. And also for inland cities as well. I remember seeing the Nike site along Chicago’s Lake Shore Drive in the late 50’s early 60s when we took a grade school trip to the Museum of Science and Industry in Chicago.
I don’t think the old Safeguard site in either Montana or North Dakota any more.
And what about California sites? How about in San Francisco? LOL!
Moffet is in a hole and crowded. Two of the best sites would already be half prepped, former Ft. Barry and Mill Valley AFS.