Editor’s Note: Katharine H.S. Moon is the inaugural holder of the SK-Korea Foundation Chair in Korea Studies and a senior fellow at the Brookings Center for East Asia Policy Studies. Moon’s research includes the U.S.-Korea alliance, politics of East Asia, and inter-Korean relations.

Story highlights

North Korea appears to have launched a submarine-launched ballistic missile over the weekend

Moon says the most recent test shows the regime is working sleeplessly towards greater nuclear capability

The launch has antagonized the EU which has been less aggressive than the U.S. on North Korean denuclearization

CNN  — 

North Korea is on a roll. Just four months into 2016, it has tested a nuclear device (its fourth), launched a satellite that uses rocket mechanisms for intercontinental ballistic missiles (ICBMS), fired multiple short-range missiles, and now claims the first successful launch test of a submarine-launched-ballistic missile (SLBM) with a flight distance of about 30 kilometers (18 miles).

Only last winter, some experts commented that the two SLBM launch attempts in 2015 revealed that the DPRK had a long way to go to achieve actual technological capability. But the fact that the regime has managed to improve the launch technology so quickly, and for the first time successfully employ solid fuel to fire the SLBM engine signals a nuclear program that is hell-bent on doing things better and faster than expected. This raises the bar for diplomacy of any kind.

A word of caution. Despite what the DPRK leader, Kim Jong Un boasts, independent experts have not yet verified whether the SLBM test on April 24 was an actual success in terms of flying a desired distance and maintaining mechanical integrity. But even if it were not as successful as Kim claims, the fact that the regime is sleeplessly working toward viable SLBM capability bodes ill for regional and international stability. North Korea already has a serious arsenal of land-based nuclear-capable missiles. Its ambition for SLBMs expresses its desire for a second-strike capability to enhance its nuclear deterrence.