What President Trump really meant is that he has painted the US into a corner with all his threats of war and really does not know what to do next.   North Korea called his 'or else' bluff.  Good.  No action on North Korea is better than any conceivable military operation.

Last week the North Korea test fired a new, longer-ranged strategic missile, Hwasong-14, that US experts claimed was capable of hitting Alaska and perhaps even San Francisco.   North Korea is now believed to have mastered a lightweight nuclear warhead that can be carried by the Hwasong and shorter-ranged Taepodong and Nodong missiles.

North Korea can't today seriously threaten North America with missile strikes, but it probably will by 2019.   Meanwhile, North Korean nuclear and conventionally-armed missiles (and this could include poison gas and biological warheads) today threaten the 80,000 plus US military personnel based in Japan, South Korea and Guam.  They would be immediate targets should the US and South Korea attack the north.