Word came out a few weeks ago that the Japanese Maritime Self-Defense Force was building a contingency plan to shoot down any North Korean ballistic missiles that might threaten Japanese territory. Japanese destroyers have the same anti-ballistic missile (ABM) capabilities as U.S. destroyers, and the North Korean satellite launch would provide an almost unique opportunity to test the system in real-life conditions. Simply promising to shoot the missile down also gave Japan the opportunity to flex its military muscle in the region. The North Korean reaction to this news was predictably hostile, both to the prospect of outside interference with the launch, and to the notion that the missile would accidentally land in Japan. Noah Shachtman now notes that the U.S. has deployed one anti-ballistic missile capable destroyer to the region, perhaps indicating that we'd like to get in on the game.

The success or failure of the ship-borne anti-ballistic missile system could have wide-ranging implications. Josh Keating opines:

It would be a lot harder for the Obama administration to continue to use the "effectiveness dodge" -- the argument that missile-defense systems should not be deployed because they cannot be proven effective -- if the Japanese are able to successfully shoot down a North Korean missile. On the other had, if the interceptors were to miss and Japan was embarrassed, it would actually make Obama's grand bargain a lot easier to pull off.

This doesn't strike me as quite right. First, the "effectiveness dodge" isn't a dodge: We have virtually no evidence that any ABM system is capable of defending anything from much of anyone. Shooting down a single missile would hardly change that. Second, if the naval system were successful in shooting down a rogue North Korean missile, then I suspect it would become much harder to argue that we need to deploy land-based interceptors in Europe. The naval system is already operational, and safely avoids the political difficulties of the land-based system, thus leaving the "grand bargain" with Russia intact.

Hopefully, however, we won't find any of this out; if the Japanese do end up shooting down the North Korean missile, things could get very dicey in northeast Asia.

--Robert Farley