Saudi Arabia's interest in a potential $15 billion purchase of the Terminal High Altitude Area Defense system -- enough sensors and interceptors to field seven THAAD batteries, a force package equal in size to what the U.S. Army aims to field in 2018 -- is a boost to the longstanding Pentagon goal to advance ballistic missile defense capacity of partner nations in the Persian Gulf. On Oct. 6, the Defense Security Cooperation Agency -- which handles government-to-government sales of military...
