Looks like the first test wasn't a fluke:
North Korea fired a submarine-launched ballistic missile on Saturday off its east coast, South Korea said, amid concerns that the isolated state might conduct a nuclear test or a missile launch ahead of a ruling party meeting in May.
The North fired the missile to the northeast from an area off its east coast at about 6:30 p.m. (0930 GMT), the South's office of the Joint Chiefs of Staff said.
North Korea will hold a rare congress of its ruling Workers' Party in early May for the first time in thirty-six years where its leader Kim Jong Un is expected to proclaim the country was a strong military power and a nuclear state.
The missile flew for about thirty kilometers (eighteen miles), a South Korean Defence Ministry official said by telephone, adding its military was trying to determine whether the launch may have been a failure for unspecified reasons.
South Korea's Yonhap news agency said the missile flew "for a few minutes", citing a government source.
Sounds pretty definitive and confirming to me. And given that they likely have miniaturized nuclear warheads already, the nightmare NoKo scenario may now be a reality.
But Jazz Shaw raises what might be a mitigating factor in our favor:
One thing the United States is very good at is tracking submarines. It’s a game that’s been going on since before any of you were born and we practice it constantly. Unlike tracking the Russians or the Chi[Comms], we would have very little difficulty keeping tabs on a group of ancient diesel boats which can’t stay below the surface long enough to make it halfway to Hawaii before they run out of air. They also tend to be noisy, giving off all sorts of telltale signals.
What we don't know, of course, is if that "group of ancient diesel boats" is all they've got in their submarine inventory. I'm not suggesting that Pyongyang has the Red October secreted in a coastal cave somewhere, but there seems little point to developing an SLBM capability if its purpose isn't to project the threat of clandestine nuclear attack across the Pacific. It would be prudent not to assume that the NoKos haven't figured out a way to make it happen.
And also that they're working alone....
What's to prevent the "good cop" in Beijing from quietly lending the "bad cop" in Pyongyang a little hand from time to time? Especially when both cops need it for a common objective.