The U.S. and Japan recently concluded an agreement to expand their joint missile defense program by installing a new X-Band radar in southern Japan, in addition to the one already located in Shiriki, Japan. Reports also suggest that the U.S. is looking to deploy another of these highly intrusive and sensitive systems somewhere in Southeast Asia, further complementing the missile-defense capabilities of Aegis-equipped U.S. warships that patrol international waters in the region. Combined, the developments suggest that the U.S. intends to build a string of missile defense systems around the arc of the South China Sea.
Obviously unhappy with these plans, China registered its protest during U.S. Secretary of Defense Leon Panetta's visit to Beijing last week. Russia, which already felt threatened by NATO missile defenses on its western borders, is also likely to resent feeling the pinch to the east as well.
What purpose does missile defense in East Asia serve for the U.S. and its allies? The official narrative in Washington and Tokyo is straightforward: Missile defense is insurance against any unwarranted aggression on the part of a rogue North Korean regime in possession of increasingly robust missile capabilities. However, the strategic calculus driving East Asian missile defense extends beyond Pyonyang and is driven by three principal considerations.