Lost in the overall frenzy of North Korea’s first intercontinental ballistic missile test last July was a peculiar detail of understated significance: While the United States, Japan, South Korea, and North Korea all agreed that the Hwasong-14 was an ICBM, one country did not.

Spoiler alert: It was Russia.

Russia instead claimed the missile was only an intermediate range (and not intercontinental) ballistic missile. In July, The Diplomat walked through some possibilities of what this might mean, be it technical error, political gamesmanship, or a genuine deficiency in capability.

After the second North Korean test of an ICBM in July, Russia again refused match the rest of the world in declaring the ICBM test as an ICBM. This repeated failure suggests a limitation in current Russian early-warning radars.

From The Diplomat:

Given the relatively large wavelength of UHF radars such as Russia’s Voronezh systems, which are primarily designed to detect incoming U.S. ICBMs, it isn’t implausible that the Russian platforms were simply incapable of detecting the comparatively smaller North Korean Hwasong-14’s second stage. (Other phenomena, such as radar refraction over the curvature of the earth, can affect the effectiveness of these radar systems.)

Gaps and limitations in Russia’s early warning capability have long been documented by foreign observers. And while North Korea has never been the adversary Russian radars are designed to watch, a failure to see North Korean ICBMs could mean Russia instead detects missile interceptors fired by the United States as a unique threat, rather than a response to a launch by Pyongyang. (Joshua Pollack explored that possibility, complete with diagrams and maps in 2009.)

In December 2016 Russia boasted that it completed construction of its early-warning coverage, and in December 2017, Russia’s Air and Space Forces announced the start of combat operations at its last three early warning sites.

And there remains a curious omission: Russia’s foreign minister Sergey Lavrov took until December to acknowledge that North Korea had any ICBMs at all, and even then, only acknowledged the November test of the much larger Hwasong-15.

All this leaves a distinct possibility that, should North Korea launch a Hwasong-14, Russia would be unable to see the smaller ICBM as what it actually is, and in what would invariably be a tense hour, might misread actions and intentions after that point. Which, in turn, casts a lot of doubt on the success and utility of even the newly completed early warning system.