North Korean missile advances put new stress on U.S. defenses

WASHINGTON — North Korea’s newly demonstrated missile muscle puts Alaska within range of potential attack and stresses the Pentagon’s missile defenses like never before. Even more worrisome, it may be only a matter of time before North Korea mates an even longer-range ICBM with a nuclear warhead, putting all of the United States at risk.

The Pentagon has spent tens of billions to develop what it calls a limited defense against missiles capable of reaching U.S. soil. The system has never faced combat or been fully tested. The system succeeded May 30 in its first attempted intercept of a mock ICBM, but it hasn’t faced more realistic conditions.

Although Russia and China have long been capable of targeting the U.S. with a nuclear weapon, North Korea is seen as the bigger, more troubling threat. Its opaque, unpredictable government often confounds U.S. intelligence assessments. And North Korea’s leader, Kim Jong Un, has openly threatened to strike the U.S., while showing no interest in nuclear or missile negotiations.

“We should be worried,” said Philip E. Coyle III, a former head of the Pentagon’s test and evaluation office. North Korea’s latest success, he said, “shows that time is not on our side.”

U.S. officials believe North Korea is still short of being able to miniaturize a nuclear warhead to fit atop an intercontinental missile. And it’s unclear whether it has developed the technology and expertise to sufficiently shield such a warhead from the extreme heat experienced when it re-enters Earth’s atmosphere enroute to a target.

A Pentagon spokesman, Navy Capt. Jeff Davis, said Wednesday, “We’ve still not seen a number of things that would indicate a fullup threat,” including a demonstrated ability to mate a nuclear warhead to an ICBM. “But clearly they are working on it. Clearly they seek to do it. This is an aggressive research and development program on their part.”

Davis said the U.S. defensive system is limited but effective.

“We do have confidence in it,” he said. “That’s why we’ve developed it.”

The Trump administration, like its recent predecessors, has put its money on finding a diplomatic path to halting and reversing North Korea’s nuclear program. While the Pentagon has highly developed plans if military force is ordered, the approach is seen as untenable because it would put millions of South Korean civilians at risk.