Hmm … now the media are finally catching on … Are we talking about something so overwhelming, so game-changing that North Korea would simply be cowed into submission?

http://www.cnn.com/2017/09/19/politics/us-north-korea-missile-mattis-options/index.html

From the CNN article:

Asked at an off-camera briefing at the Pentagon if there are military options that would not put Seoul at “grave risk?” He answered: “Yes there are, but I will not go into details.”

Mattis would not clarify if the options he was referring to are kinetic- meaning strikes using conventional weapons.

The Pentagon is looking at potential covert cyberattack options. But other non-kinetic options could include a show of force in the air or on land in the region or increasing the US military presence in the area by deploying more ships or troops.