North Korea conducted its sixth nuclear test on Sunday, claiming that it had detonated a hydrogen bomb that was small and light enough to be mounted on an intercontinental ballistic missile. Pyongyang has made such claims before without proof that it actually possesses those advanced capabilities. Sensors in South Korea, China, and the US indicated, though, that whatever the Hermit Kingdom exploded underground on Sunday was more powerful than the atomic weapons the US used during World War II—a benchmark North Korea had not definitively topped before.
The blast comes on the heels of an unsettling ballistic missile test last week, in which North Korea flew a mid-range projectile over northern Japan’s Hokkaido Island. But both recent tests fit into a larger picture over the last three years of North Korea’s increasing determination to become a fully capable nuclear power. The Obama administration, which pursued so-called “strategic patience,” began to see the necessity of stepping up pressure on North Korea to stop this evolution in the final years of the second term. Trouble is, there are limited options for attempting to address tension with North Korea, and while President Donald Trump has thus far largely followed established paths, namely by levying sanctions, his trademark inflammatory language seems to have emboldened Kim Jong-un rather than cowing him into any type of compliance.
“The test looks like it was about 10 times larger than the previous test [in September 2016],” says Abraham Denmark, the director of the Asia Program at the Wilson Center and a former Deputy Assistant Secretary of Defense for East Asia under President Obama. “Scientists will be poring over the data for several days, but it is clear that the explosion was much larger than anything North Korea has tested before. This means that North Korea is one step closer to fielding a credible nuclear capability that threatens all of East Asia and the United States.”
Analysts worked on Sunday to reconcile varied data about the blast and began to draw preliminary conclusions. The explosion occurred at the underground Punggye-ri testing ground in northwest North Korea. The United States Geological Survey detected that the tremor from the blast had a 6.3 magnitude, while the South Korean Defense Ministry sensed a 5.7 magnitude. Even the lower estimate would still indicate an explosion many times more powerful than North Korea’s 2016 tests. USGS and Chinese instruments also picked up a second, magnitude-4.1 tremor, which may have been caused by a structural collapse in the underground facility.
Ahead of the test, North Korea released photos of Kim Jong-un posing for scale (as well as dramatic effect) with what appears to be a miniaturized, staged thermonuclear weapon (hydrogen bomb). Though the reclusive nation claimed in early 2016 that it had a hydrogen bomb, blast data never really supported this; experts found it more likely that the country was experimenting with using tritium, a radioactive isotope of hydrogen, to boost the power of conventional atomic bombs. Though experts were clear on Sunday that it is too soon to draw technical conclusions about the most recent test, some argued that from a geopolitical perspective it is time to assume that North Korea possesses functioning staged thermonuclear weapons.
“The pictures look like a staged thermonuclear weapon and, you know, maybe it was filled with gum balls, but it was the right size and the right shape,” says Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute for International Studies in Monterey, California. “They’ve done five other nuclear tests, and if you look at where other nuclear powers were after five tests, a staged thermonuclear weapon is a plausible thing for them to have built at this point. Plus the explosion was an order of magnitude bigger than anything they’ve ever exploded before. If this were any country other than North Korea we would believe it. The Soviets never let us inspect the device before they tested it, we just believed them.”
The list has dwindled in terms of technological capabilities North Korea needs to display to show its readiness as a fully outfitted nuclear power. Of course, questions still remain about the reliability of its program, particularly in terms of missile targeting and guidance, the ability of its warheads to withstand reentry into the atmosphere, and warhead miniaturization, but the pace of the nation’s progress is clearly quickening.
North Korea is known for conducting weapons tests with far-reaching geopolitical implications around its national holidays—and often near US holidays—to create disruption and confusion. So a test over Labor Day weekend in the US, which happens to fall near the anniversary of the North Korean government’s founding, is not altogether surprising. In discussing North Korea’s missile flyover of Japan last week, many US analysts predicted that a sixth nuclear test could be coming in the next few months. Regardless of how inevitable it may have felt, though, North Korea’s actions are firmly in violation of United Nations Security Council resolutions, and leaders from around the world strongly condemned Sunday’s nuclear test.
“North Korea has conducted a major Nuclear Test. Their words and actions continue to be very hostile and dangerous to the United States,” President Trump said in early morning tweets. “North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help but with little success. South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!”
With limited options for reacting to North Korea, many experts have been in agreement for months that direct and intense in-person negotiations with the reclusive regime are the only viable path forward. Though economic pressure is helpful, an agreed-upon freeze on weapons testing would have been the only way to stop North Korea from gathering the crucial, real-world test data it has collected in recent months, not to mention this past week. “The problem now is they have tested everything they need to test—the only question is reliability,” Lewis says. “Which should not make anybody feel good, because a stockpile of unreliable weapons should be enough to deter us. And so we’re in this very difficult situation where nuclear weapons force us to go talk to the North Koreans, and that’s going to be really embarrassing and hard for [the Administration]. They’re big on the tough talk.”
President Trump’s morning comments via Twitter seemed to criticize the new, left-leaning South Korean administration for considering negotiations of some sort with Pyongyang. He added on Sunday afternoon that he would meet with his military advisors to discuss the situation. Where his first tweets implied that only physical engagement could get through to North Korea, his second round of comments focused on economic pressure. Neither set of remarks was a public indication that the administration views diplomatic negotiations as a possibility. “The United States is considering, in addition to other options, stopping all trade with any country doing business with North Korea,” he said in a tweet. Analysts reacted immediately with concern, noting how problematic and economically destabilizing such a sweeping gesture would be. North Korea’s trade partners include India, Taiwan, and Mexico, not to mention China. US trade in goods and services with China amounted to $650 billion in 2016, and the country owns about $1 trillion in US debt. Though putting pressure on China to stand against North Korea has been a favored strategy of President Trump, such a radical act would plainly be a gamble for the US as well.
Analysts emphasized, though, that diplomatic negotiations could be possible if the Trump administration will just consider them. “The United States also has the option to engage North Korea diplomatically, which the President seemed to take off the table several days ago,” the Wilson Center’s Denmark says. “But many believe [this] is the only way to peacefully address this crisis.” He also noted that President Trump has the ability to appoint several government officials to roles that have gone unfilled for eight months (like Assistant Secretary of State for East Asia and the Pacific and Assistant Secretary of Defense for Asia-Pacific Security Affairs), who could directly participate in tackling the North Korea situation.
For the North Korean government, Sunday’s test was gratifying. State-sponsored news wrote that Kim Jong-un “expressed great satisfaction over the fact that our scientists do anything without fail if the party is determined to do [it].” The question is whether the party is determined to show off what those weapons can really do.