For all we know, they were testing a nuclear trigger. Our nukes have triggers that put out as much power as the nagasaki bomb.
And, for all we know, Obama will get his high powered foreign policy team together (aka Hillary) and start tough negotiations with North Korea. But first, they’ll need to offer them something as a sign of good faith...something like our nuclear trigger technology...yeah, that’ll get North Korea to come back to the bargaining table...