I trust everybody remembers the (fake) reasoning given by the Americans to deploy a missile shield in Eastern Europe: to defend Europe from Iranian missiles (not that Iran ever had any desires to attack Europe).
Similarly, the THAAD deployed in SK (without said country's approval) is supposedly against NK, but in reality it is against China.
Curiously enough, the European 'shield' is placed very close to the Russian border; not the Iranian.
Ditto this thing in Alaska.
Just as the Pershing deployment during the Cold War.
Seems, like nothing has changed.