As the latest edition of North Korea’s submarine-launched ballistic missiles (SLBMs) slowly paraded past the iconic Kim Il Sung Square in central Pyongyang on Jan. 14, state TV announcers proudly labeled it the “world’s most powerful weapon.”
Of course, according to experts, the missile is too large to fit in any submarine North Korea currently has, so it’s not quite the most powerful weapon yet. But nor is it a dud: With the latest generation of SLBMs, North Korean leader Kim Jong Un is inching closer to something genuinely powerful—a solid-fuel missile capable of reaching most of the mainland United States and with a shorter launch time than the current bevy of liquid-fuel rockets.
“This will ultimately pave the way for the North Koreans to eventually begin testing land-based intermediate-range solid-propellant missiles and eventually intercontinental-range solid-propellant missiles,” said Ankit Panda, an adjunct senior fellow at the Federation of American Scientists.
What that means in practical terms is a much more resilient nuclear deterrent—complicating even further any U.S. response in a potential future crisis.
“Not only would Kim improve the flexibility and the responsiveness of his nuclear forces. He would also improve the survivability of his nuclear forces,” said Panda, the author of Kim Jong Un and the Bomb. “Survivability is a key concern for any nuclear weapon state.”
Kim has made big strides in his missile program in recent years, with the latest design capable of carrying multiple warheads as far as the continental United States. But the liquid-fuel missiles have two big drawbacks: They take a long time to prepare, and the huge launchers are easily spotted from the air. That means the North’s missiles are hardly mobile and could be neutralized before becoming a threat.
Solid-fuel missiles, in contrast, can be launched quite quickly—not for nothing did the United States name some of its intercontinental ballistic missiles (ICBMs) “Minutemen,” which, like their colonial predecessors, could be ready at a moment’s notice.
If experts look askance at the demonstration of a submarine-launched missile without a submarine to launch it (yet), it’s because any sea-launched weapon would have to get around the U.S. Navy first.
“It’s just not survivable against the United States. In any crisis or conflict, I can only imagine that the U.S. Navy or the [South Korean navy] would be there just blanketing the entire coast. I can’t imagine anything is going to survive,” said Vipin Narang, an associate professor of political science at the Massachusetts Institute of Technology.
But many experts believe North Korea isn’t angling for an SLBM just yet—but rather to refit the regime’s current missiles to solid fuel.
“There’s no reason why an SLBM can’t be used as a land-based missile, so I think the end game is working on solid-fuel long-range missiles,” Narang said, comparing North Korea’s missile development time to the churn of new iPhones.
India, he noted, had done this but in the other direction, using solid-fuel missiles as a basis for advanced submarine-launched weapons. “You kind of kill two birds with one stone with the same kind of design,” Narang said.
That doesn’t mean they’re easy birds to kill. But Pyongyang has surprised in the past with its technological development.
“With the North Koreans, there is a constant tendency to underestimate their technical capabilities. They tend to have very long timelines, but they essentially overdeliver on their promises,” said Go Myung-hyun, a research fellow at the Asan Institute for Policy Studies in Seoul.
“It’s conceivable that North Korea can achieve solid-fuel ICBM capability sooner than you expect,” he added. Every missile test since October 2017 has been solid fuel.
Not everyone thinks the new missiles are a test bed for development. South Korea lacks good defenses against submarine-launched missiles, so if the North were able to deploy a suitable submarine, and if the missiles really worked, that could present a cross-border threat.
“Right now, South Korea has no defenses against an SLBM, so it is a threat. South Korea would be exposed to even short-range SLBMs. I think it’s more of a regional threat than an intercontinental threat,” said Bruce Klingner, a senior research fellow at the Heritage Foundation and former CIA deputy division chief for Korea.
It’s not even clear if the new missiles really work, though the answer is probably yes—since they’re just iterations of a previous type that was successfully tested in 2019. But Kim also needs to test his latest intercontinental missile, first unveiled in October 2020. That has led many observers to wonder: With a new U.S. administration taking office, will there be a fresh round of North Korean provocation?
“Using history, it would be logical or expected that North Korea would do something within the first few months” of the new administration, Klingner said.
“If they do it, we’ll say, ‘That was very perfectly predictable because that’s what they’ve done in the past.’ If they don’t do anything for quite some time, we’ll say, ‘Well, that’s unusual but perfectly predictable given COVID restrictions,’” Klingner added.
