Few anticipated that 2016 would see such unprecedented missile and nuclear testing in North Korea, most recently its fifth and largest ever test, reportedly coming in at 10 kilotons. But none of this should have come as a surprise. Under Kim Jong Un, North Korea’s approach to developing its strategic forces is markedly different—more aggressive—than it was under his father or grandfather. The striking change puts the Korean Peninsula on a path to nuclear war unless the U.S.-South Korean alliance can adapt to the constraints of deterrence and defense against a second-tier nuclear-armed adversary.
Whereas Kim Jong Il’s North Korea conducted 18 missile tests during his 18-year reign, the last four years under Kim Jong Un have already seen 35 missile launches and three nuclear tests. In word and deed, Kim Jong Un has laid bare his intentions to mate nuclear warheads to long-range missiles, pursue a hydrogen-based nuclear bomb, and develop a submarine-launched ballistic missile capability, which has long been considered the gold standard of an assured retaliatory capacity. Gone are the days in which it is possible to speculate that North Korea’s nuclear weapons were mere symbols or bargaining chips, or that the threat of nuclear attack was “deeply hypothetical,” as a White House spokesperson during the George W. Bush administration once described it.
North Korea’s nuclear program is now more accelerated, less constrained, and more openly linked to its missile program than at any point in its history. Pyongyang is rushing to deploy a nuclear force that can ensure the regime’s survival by guaranteeing that any attempt to replace it or invade to North Korea leads to nuclear war. But Washington and Seoul are dealing with North Korea as if it were still the 1980s.
For a long time, North Korea’s foreign policy playbook has included recurring small, isolated, and deniable attacks against South Korean and U.S. targets. Historically, these attacks were backed by a willingness to wage conventional war if