About That Golden Dome

I have a number of questions about the missile defense system President Trump has been calling for, recently termed “Golden Dome”. I’ll just bullet my questions. The parallel with Israel’s “Iron Dome” is obvious (that’s what the system is called in the original executive order).

• My understanding is that Israel’s Iron Dome system cost roughly $500 million in 2011 dollars with an operating cost of $150,000 per interception. That was for 10 stations (the ultimate objective was 15 stations). If 15 stations are required for a country the size of New Jersey, what would the cost of a system that would protect the United States? That’s, what, four orders of magnitude larger? It wouldn’t be linear increase but a geometric one.
• How effective would such a system be and need to be? The Israeli system is said to be 90% effective. To put that in context you could protect 90% of Illinois without protecting the City of Chicago at all.
• Is it technically possible to defend the U. S. with such a system without also protecting Canada? And a good chunk of Mexico? Whether either country participates in the system or not?
• The system sounds much like the “Star Wars” system proposed during the Reagan Administration. Is that strategy fighting the last war? Or, more precisely, is it fighting today’s war with yesterday’s weapons systems?
• Are the Chinese right? Would such a system be a violation of existing treaties? It sounds like it to me (we’ll leave aside the question of whether China and Russia are already violating those treaties).