In an extraordinarily brief statement, the Director of the National Intelligence Office announced that the United States has confirmed that North Korea’s large explosion last week was nuclear. How do they know and why did it take them so long to confirm?
Last Sunday, North Korea apparently tested a nuclear explosive. The “apparently” is needed because the explosion was so small—by nuclear standards—that some have speculated that it may have been a large conventional explosion. What is the technical significance of the test, what does it mean, and what should we do now?
There is no question that the political and security implications of the test are huge and almost entirely negative. The technical implications are more mixed; the technical significance of the test is somewhat less than meets the eye.