Reports of the United States’ redeployment, even if only temporarily, of its Terminal High Altitude Area Defense (THAAD) missile defense system from Seongju, North Gyeongsang Province, to the Middle East have garnered considerable attention in Seoul and Washington. These concerns have only grown after North Korea launched 10 ballistic missiles into the sea during the South’s joint military drills with the United States on March 14. Given the central role missile defense systems play in maintaining deterrence from North Korean threats, it’s understandable that any decision or move regarding THAAD would raise questions about the security and safety of the Korean Peninsula. However, the move should not be interpreted as a precursor to abandonment, as some may argue. Instead, it shows how cooperation and the Korea-U.S. alliance are adapting to a complex world where security challenges span multiple regions. American defense planners have long had to maintain preparedness for “strategic flexibility.” The THAAD system was always designed to be highly mobile and deployable, reflecti