By Mark Fitzpatrick, Executive Director, IISS-Americas, and Michael Elleman, Senior Fellow for Missile Defence
There is no need to remind; North Korea knows the United States is mighty. It knows this first-hand, from the bombing raids in the Korean War that flattened the country so thoroughly that the US Air Force ran out of targets. Democratic People’s Republic of Korea (DPRK) state propaganda outlets constantly rail against American hostility, to the point of paranoia. There is no reason to think leader Kim Jong-un doubts America’s resolve to respond to attack.
So if President Donald Trump’s threats of ‘fire and fury’ are intended to reinforce deterrence, they serve no useful purpose. Rather, such statements are counter-productive, in at least three ways. Firstly, they reinforce the North Korean sense of paranoia and thereby heighten the potential for war. The gravest danger in this situation is that the DPRK will come to perceive itself to be under attack. If so, its natural response will be strike first, even launching nuclear-armed missiles in the fear that otherwise these assets will be pre-emptively destroyed and it would have no second-strike capability.
Secondly, the threats alarm US allies in the region in ways that undermine the alliance structure. South Korea and Japan are adamantly opposed to the US starting a preventive war in which they would bear the brunt of North Korean retaliation. From what we hear in Washington, diplomats from both countries have been plaintively asking what on earth Trump is up to. Perceptions of credibility rest not just on the means and will to act, but on the wisdom of action. Each time the president utters a threat that puts South Korean and Japanese lands and lives at risk, it weakens faith in the US partnership.
Thirdly, bombastic threats undermine the president’s credibility. The red line Trump drew on 2 January –that North Korean intercontinental ballistic missile (ICBM) development ‘won’t happen’ – was crossed twice last month with successful ICBM tests. The ‘fire and fury’ threat immediately provoked North Korea to claim plans to simultaneously test four missiles in the direction of Guam. President Barack Obama was pilloried for failing to enforce his redline against Syrian use of chemical weapons, but he at least succeeded in bringing about the surrender of the vast bulk of that country’s chemical-weapons arsenal. North Korea, by contrast, has only expanded its strategic capabilities in the face of Trump’s thunder.
North Korea’s response now could well escalate the war of words beyond the realm of rhetoric. A statement issued on 10 August by the Korean Central News Agency said four Hwasong-12 missiles will cross over Japan and ‘hit the waters 30 to 40 kilometers away from Guam’. This would be dangerously close for a test. There is a finite probability that one of the missiles will overshoot its target and strike land.
A missile’s accuracy is determined by many factors, including those associated with the navigation and guidance unit, about which little is known in the case of the Hwasong-12, which has failed in three of four test flights. While navigation and guidance errors will negatively impact accuracy, they are small relative to errors associated with the process of shutting down the missile’s engine. Errors in the timing of engine shut down, and variations in residual thrust after shutting off the flow of propellant, have the most impact. For a Hwasong-12 flying toward Guam, we would expect to see timing and residual-thrust variations resulting in an average miss distance of seven to 10 km. Larger errors are possible, such that the probability of accidently hitting Guam is just under one percent. This may not seem large, but given the consequences of an accidental strike, the risk of escalation is enormous.
If any of the launches were on an azimuth toward Guam, which would be ascertained by radar within about 100 seconds of launch, the US would need to activate missile defences to try to shoot them down, using Terminal High Altitude Area Defense (THAAD) batteries in Guam and possibly SM-3 Block IA or IB batteries on Aegis ships. It would be the first time such systems had been used in an actual live-fire situation, and the probability of success, especially against multiple incoming missiles, is not known.
Recognising the possibility that they could be intercepted, North Korea would probably send missiles in an azimuth that would avoid Guam entirely, hitting the open seas. The US might still try to intercept them, if Trump decided he needed to do so to back up his warning. If the interception were to fail, however, it would undercut credibility of US defences. If the interception worked, as we would dearly hope, it would be the first direct kinetic clash between US and North Korean military forces since a US helicopter was shot down over North Korea in 1994.
What North Korea’s next move would then be is unpredictable, particularly if it believed the interception was a prelude to further military action. To avoid deadly misperception, the US needs a channel of communication with Pyongyang. A public shouting match is no help.