“If they do get to the point where they decide to start a campaign of ICBM flight testing, that will allow them to work through the usual technical difficulties,” he said, noting that they had an “impressive” record of solving problems. “It will allow them in time, I’m confident, to create a reliable weapon.”
But Pollack was wary about any timeline. “They could flight test an ICBM today and it could work or it could take them a year or two,” he said. “I really hesitate to say anything about it.”
Other experts have offered cautious estimates, based on the rate of testing in the last six years. “If everything proceeds as is, it’s likely by 2020 that they could have a system reaching the United States,” Bermudez said. “It should be viewed as an emerging threat.”
After the fifth test last fall, Siegfried Hecker, the former director of Los Alamos National Lab, the cradle of the first atomic bomb,
gave a similar assessment. “Left unchecked, Pyongyang will likely develop the capability to reach the continental United States with a nuclear tipped missile in a decade or so,” he wrote in a post for 38 North.
While North Korea cannot hide its missile tests – even short-range tests are usually visible to satellites – it has performed nuclear tests in
a tunnel system beneath a mile-high mountain. The secrecy means experts know relatively little about how small or sophisticated North Korea’s bombs are, or how many exist. Experts agreed, however, that North Korea probably has the means to fit a warhead to an ICBM.
“It’s within the range of their technical capabilities and competence,” Bermudez said. “That doesn’t mean they could easily or successfully do it.”
The US has reportedly made it more difficult for North Korea to get missiles off the ground, with
a series of cyber-attacks begun by Barack Obama. But government hackers alone probably cannot stop North Korea’s ambitions, Bermudez said. “It’s likely that any cyberwarfare campaign would not be able to stop either the nuclear program or the ballistic program, only delay it.”