Truman used similar words to describe the atomic bomb used against Hiroshima.

Apart from NK, Trump is also speaking to Iran (in particular), Pakistan, China, Russia, and various terrorist groups.
Trump pulled the trigger for unprecedented attacks in Syria (after Assad's use of sarin gas against civilians) and in Afghanistan ( to kill as many terrorists as possible.)

Thomas Jefferson and Theodore Roosevelt are the only presidents I can think of who were genuinely "curious" intellectually.  Which other presidents do you believe were "curious?"

From Attila the Hun to Caesar to Elizabeth I to Napoleon to Bismarck to Zhukov, "Fire & Fury" has been the most
successful military strategy.  If you wish to have victory, then completely obliterate your enemy.  Trump gets it.

The highest probability, especially if NK actually carries out its threat to 'encircle Guam with missiles,' is Mattis'
prophecy:

"Overwhelming force will be used to change the regime and North Korea will be destroyed."