North Korea’s weapons programs are distinguished by their sophistication in manipulating both technical and political goals. Technical goals have been deliberately dialed back in favor of political objectives and vice versa.
Their long term objective is to achieve political aims: expulsion of US from the Korean peninsula and unification of the Koreas on DPRK terms, ideally without having to fire a shot.
DPRK called their goal military “equilibrium” with the US that remove military options for dealing with the regime from the US, and by insinuation, PRC, Russia, Japan and ROK. Equilibrium in this context is not to say the same size / scale of nuclear arsenal as the US, but a credible and assured capability to inflict on the US (or others) unacceptable destruction.
For this political objective, a large arsenal is not required — only an arsenal that the target believes will be sufficient to (e.g.) destroy a major urban center like (e.g. San Francisco or New York City) that will be unacceptable.
The USSR was able to achieve this level of deterrence with a crude arsenal in the 1950s with SS-N-3 cruise missiles based on Whiskey class submarines and Tu-95 Bear bombers.
PRC, likewise, deterred aggressors with a handful of liquid fueled missiles from the 1970s well into the 1990s.
DPRK’s goal of precluding a US conventional attack that require a large military buildup beforehand have been achieved by their present credible capability to deliver a nuclear strike on US bases in Japan, ROK, and Guam. This, taken with North Korea’s publically stated intention to preemptively strike US bases or ROK and Japan have complicated many military options.
President Moon’s government – the prime target of DPRK’s political strategy – played right into their hands by demanding a veto on US use of force against DPRK. While this stance may have merit prior to DPRK acquiring a capability to threaten CONUS, it is fantastic and delusional to think that any US President will accede to a ROK veto for a retaliatory strike after a nuclear attack on US soil. Yet, Moon had the audacity to demand it.
This shows DPRK’s political strategy is working.
The “sunshine policy” announced by President Moon in Berlin and proposed legislation to bind ROK to “the summit agreements of 2000 and 2007”, when combined with the demand for early transfer of OPCON to ROK in effect, precludes US military options except for the use of WMDs on DPRK proper — with collateral damage against allies like Japan.
In the absence of realistic military options by ROK-US forces, DPRK will benefit from the financial boost from “sunshine” and rather than weaken, have the resources to expand and improve their WMD arsenal — and thus, achieving their goal of credibly threatening the US, which in turn, sets the stage for forcing the US out of the Korean peninsula and reunification.
The political goal of the coming round of tests need to be non-threatening to ROK so as to strengthen President Moon and his capitulationist policy, while at the same time, give Americans second thoughts by holding a major city in CONUS at risk with ICMBs. At the same time, Russia and China have to be not threatened directly even as DPRK gains an assured second strike capability against Beijing.
In order to achieve these technical goals, DPRK must “range” a missile that can plausibly threaten a major city in a weakly defended part of CONUS, while at the same time, demonstrate “end-to-end” capability with a nuclear warhead that can survive re-entry and detonate. That speaks to an ICBM with a range of 12,000km with a low (or near zero) yield warhead that can still muster the characteristic “double flash”, X-rays, etc. that indisputably announce a nuclear blast that will be detected by US space based sensors.
DPRK have to be cognizant of the risks that the “missile test” may be intercepted. Allies attacking a North Korean missile “left of launch” or during boost phase, carries considerable risks, i.e. any interception in DPRK territory is a violation of the armistice. Letting the missile travel outside of DPRK territory before striking it with missiles systems like Aegis or THAAD may not be possible depending on which direction the missile travels. Interception with GMDs in Alaska require depleting scarce interceptors.
In any case, if the test involve a live warhead, DPRK is likely to minimize the risk of mid-course interception by choosing a direction that makes it difficult. Left of launch and boost phase interception risks can be limited by volley firing multiple missiles. Ensuring the political and technical goals of such a demonstration are met suggest DPRK will choose a path that minimize interception risks.
An ICBM test overflying ROK and Japan will have to count on allies “letting it go” as per standard practice, which may or may not happen this time. A minor consideration for an unarmed missile, but not for a nuclear tipped missile test. There is the option of aiming for the oceans west of Perth, Australia, or overflying PRC onto the Indian Ocean. Another path is to overfly sparsely populated Siberia and land the missile in unpopulated areas like James Bay, or in the Atlantic Ocean just south of Greenland. Such a route would have the benefit of indisputably demonstrating range and the weakness of GMDs based in Alaska while being difficult to intercept mid-course – particularly with debris that will fall on Russian soil.
Demonstrating the weakness of US missile defense for East Coast cities will have the most deterrent effect on the US in the short run.
An end-to-end test is a major escalatory step that can serve to either deter or trigger allied military action.
Successful interception of such a test would weaken the DPRK threat, while a failed intercept will impair US credibility in missile defense.
North Korea, will likely aim in such a way as to limit the chances of a successful intercept by firing the ICBM either into the Indian Ocean or into the North Atlantic.
Given the uncertainties in North Korean expertise in predicting yield and the difficulties of calibrating a low yield “demonstration” explosion that don’t fail (e.g. zero yield), the warhead will likely have to be well above “low” yield (i.e. .3 to 1kt) to an “assured success” explosion in the 5kt range. Detonation of such a device in a heavily trafficked maritime area or near a population center will likely bring military action, which DPRK do not want.
Their goal is to stymie allied military action, not to trigger it.
Detonating a 5kt range device limits the options once heavily used shipping lanes (and fishing areas) are excluded. Unlike the North Korean missile test threatened for Guam, no prior warnings are likely to be given so shipping can avoid the area. That in turn, limits the areas that can be used likely to a point west of Australia (to limit overflight over PRC and avoid air/sea lanes). Alternatively, an area like James Bay or just West of Greenland.
Finally, there is the question of timing.
Launching such a test in December to coincide with Kim Jong Il’s death, or alternatively Kim Jong Il’s birthday in February are likely under consideration. The February date will be optimal in that it coincides with the Winter Olympics in ROK, and Lunar New Year. This would provide maximum exposure for DPRK’s tests while at the same time, signaling to ROK that they are not the intended target.
If North Korea successfully execute their ICBM and nuclear warhead tests, it will signal the beginning of the closing of the window for military options and the start of a new era in international relations.
We are running out of road.