The commander of US forces on the Korean peninsula says that the North Koreans probably possess the technology to place a nuclear warhead on an ICBM.

That kind of miniaturization of a nuclear warhead is a daunting technological challenge, but General Curtis Scaparrotti told reporters at the Pentagon that the regime of Kim Jong Un has likely mastered it.

Wall Street Journal:

Speaking to reporters at the Pentagon, Gen. Curtis Scaparrotti, commander of U.S. forces on the Korean peninsula, said North Korea now is capable of building a miniaturized nuclear warhead, a step needed to complete development of a nuclear-tipped missile.

Such nuclear warheads would be small enough to fit on a ballistic missile and would be a major improvement to Pyongyang’s weapons technology. Gen. Scaparrotti said he believes North Korea also has developed a launcher that could carry an intercontinental ballistic missile with a miniaturized warhead.

He also said dictator Kim Jong Un “is clearly in control of the country,” despite recent rumors that his grip on the nation has slipped.

The general noted that the U.S. hasn’t seen North Korea test a miniaturized nuclear weapon. Rear Adm. John Kirby, the Pentagon press secretary, said later that there is no “smoking gun piece of evidence” backing Gen. Scaparrotti’s revelation, but said there is no reason to doubt the North Koreans were close.

If North Korea has a launcher as well as a functioning, long-range missile and a miniaturized nuclear warhead, the combined components would significantly increase its capabilities.

Intelligence assessments of North Korea’s capabilities have fluctuated recently, but Gen. Scaparrotti is seen as a voice of authority when it comes to matters involving security in the Asian region.

North Korea has struggled for years in its attempts to develop nuclear warheads and long-range missiles, as well as with the steep technical challenges of combining warhead and missile technology. But Gen. Scaparrotti said it is likely that Pyongyang now has the capability.

“I believe they have the capability to have miniaturized the device at this point, and they have the technology to potentially actually deliver what they say they have,” he said.

Gen. Scaparrotti said North Korea may have gained know-how on warhead-miniaturization technology through its relationships with Iran and Pakistan. But because the technology is so sophisticated, it would be hard for the North Koreans to use the system effectively without exhaustively testing it first.

“I think, given their technological capabilities, that the times that they’ve been working on this, that they probably have the capabilities to put this together, he said, but noting that “I don’t believe that they have. I don’t know that they have at this point.”

Highly specialized machine tools are necessary to build a nuclear tipped missile, due to the exacting engineering requirements. Clearly, North Korea is incapable of building such machines. But Pakistan already has nuclear missile technology and could easily have sold it to the Kim regime. They have demonstrated in the past their willingness to engage in nuclear proliferation activities, and it is believed they sold hardware to the Iranians.

If true, this will set off a nuclear arms race on the Korean Peninsula. The South will not rely on an American nuclear umbrella - not with China backing the North. They will feel compelled to construct their own weapon - a process that has probably been ongoing for decades. 

Just a reminder: The two Koreas exchanged gunfire across the border a couple of times over the last month. How easy would it be for a confrontation to escalate to a nuclear exchange? Given the fanaticism of the North Korean regime, I wouldn't bet against it.