In Showing Off New ICBM, North Korea’s Kim Jong Un Returns to Old Tactic

But nearly three years in, the prospects of a deal appear slim, and Mr. Kim is turning again to weapons advances to improve his negotiating position.

The Saturday procession featured one reveal after another: upgrades to soldiers’ infantry gear, a next-generation submarine missile and what weapons experts say is the world’s largest mobile ICBM.

“The parade displayed a diverse range of options that Kim Jong Un could reach for in a crisis,” said Adam Mount, a senior fellow at the Federation of American Scientists. “This is not his father’s arsenal.”

The new ICBM is a successor to the Hwasong-15—the missile that demonstrated the North’s potential to hit the U.S. mainland—and boasts a similar range. But it is significantly longer and thicker, and could possibly carry more than triple the payload, or number of warheads, according to researchers at 38 North, a North Korea-focused website, based on an initial assessment.

By unveiling a more menacing weapon, Mr. Kim is hoping the threat—and any test launches—drives up the price for the U.S. of relinquishing them.

It remains unproven whether the new ICBM is ready for testing, let alone a strike. But it deepens the view in Washington, Seoul and elsewhere that Mr. Kim remains unlikely to give up his nuclear arsenal, said Wi Sung-lac, a former nuclear envoy for South Korea.

“There already is a growing voice that it’s impossible to persuade North Korea to give up its nukes, so we should try to contain them,” Mr. Wi said. “North Korea is hoping this one day becomes official American policy.”

North Korea, in a state-media report after the parade, said the country’s strategic nuclear forces underpin its authority and security. It didn’t specifically mention the new ICBM.

The State Department said it was disappointing that the North is giving priority to its nuclear and ballistic missile program. South Korea’s national-security council and the Pentagon said their analysis of North Korea’s new weapons is continuing.

North Korea has in recent years steered clear of the type of saber rattling that brought the Korean Peninsula to the brink of war in 2017, as Pyongyang has sought to maintain good ties with Mr. Trump.

It hasn’t conducted a nuclear test or launched an ICBM in around three years, a development applauded by the Trump administration. Mr. Kim had declared a moratorium on such tests, though backed off from that promise in a policy speech published Jan. 1. But North Korea hasn’t conducted a major launch this year. In July, Kim Yo Jong, the dictator’s sister, said, “We do not have the slightest intention to pose a threat to the U.S.”

But the Kim regime, dealing with a faltering economy, flood damage and the coronavirus pandemic, stands at a crossroads weeks before the U.S. presidential election. Talks remain gridlocked with Washington, and the next president will determine its next steps. At Saturday’s ceremony, the North opted to display the military hardware that could feature in future provocations.

Despite Mr. Kim’s claim of completion, North Korea still has many areas for improvement for its nuclear arsenal, weapons experts say.

Still unknown is whether the North’s nuclear warhead could survive re-entering the atmosphere, where it would need to withstand enormous pressure and heat, those experts say. The Kim regime also has yet to show it can affix multiple warheads to an ICBM, which would bring the threat of simultaneous strikes. Unveiling missiles that can be powered with solid fuel, rather than liquid fuel, would demonstrate technology that enables Pyongyang to launch an ICBM more quickly.

The biggest holdup in demonstrating those abilities has been the Kim regime’s pause on long-range testing, security experts say. “Every weapon has to be tested under realistic conditions multiple times to be proven,” said retired South Korean Gen. Chun In-bom.

One risk to the long-range launches relates to the test’s flight distance. Under Mr. Kim, the North had adopted more lofted-trajectory launches that can measure whether a missile can fly a long distance by shooting it high up, rather than at a flatter—and outward—path. That means Pyongyang can conduct tests without the risk of having its test missile veer into, or near, U.S. territorial waters in the Pacific.

Other key elements of a nuclear launch, like the re-entry capability, are more credibly demonstrated with a launch that travels along a flatter and horizontal path, weapons experts say.

But the new ICBM showcased at Saturday’s parade can use a lofted-trajectory launch that eventually splashes into the nearby waters between Japan and the Korean Peninsula, like in previous tests, said Jeffrey Lewis, director of the East Asia Nonproliferation program at the Middlebury Institute of International Studies in Monterey, Calif. “So it probably doesn’t go any further than the Hwasong-15, but just carries a lot more,” Mr. Lewis said.

But it likely won’t be long until the North decides to test out its new ICBM, said Lee Sung-yoon, a North Korea expert at Tufts University’s Fletcher School. “With the latest demonstration, it is, for now, party time in Pyongyang,” Mr. Lee said.

Write to Andrew Jeong at [email protected] and Timothy W. Martin at [email protected]