North Korea is for a second day is blocking workers from the South from going to their jobs in the Kaesong Industrial park.  That’s despite Seoul's calls to lift the passage restrictions.  The situation is troubling, because many observers believe that keeping Kaesong open was a sign that the current Korean crisis was really all words, no action.

This week is first time the North has closed the border crossing leading to the jointly run industrial park since 2009.  It was the last functioning crossing and Kaesong is the last significant symbol of cooperation. 

Kaesong is also a key source of income for Pyongyang, especially since the latest round of economic sanctions approved by the United Nations, and the less-publicized drive by the US to crackdown on trade with foreign branches of North Korea’s state run bank.

Hours after this, the US Defense Department announced it is sending an advanced missile system to Guam as a precaution.  The Terminal High Altitude Area Defense System (Thaad) has been slated for Guam anyway, but the current circumstances added urgency to the decision.

Two US Navy Destroyers are deployed off the Korean Peninsula.