If we doubt the truism that history repeats itself, then let us examine a book published a year before the onset of World War 2 in Europe.  Here is a quote:

In a tense atmosphere of dictatorial demands and acts, the people are held in the constant fear that some spark may be ignited that may set off a ... Second World War.

What will Hitler’s next move be?  No one knows.  But we must remember that the Fascist dictators ... must act dramatically[.] ... Therefore, they act boldly and cast caution to the winds; they bluff and storm; they challenge and defy the leaders of other countries.  And these leaders of other countries, fearful of a spark that will ignite another world explosion, are cautious, uncertain, and seem to have no definite policy. ...

What will be the outcome?  No one can guess[.]

We need not guess.  In 1938, after the publication of the book, Nazi Germany invaded Poland, forcing the Western Allies into a brutal war that cost an estimated sixty million lives.  It could all have been prevented, or at least strongly mitigated.

In the text cited, substitute the terms "North Korea," "Kim Jong-un," and "a Third World War," change the year to 2017, and then ask yourself, does history repeat?

The book cited: Rugg, Harold.  Changing Governments and Changing Cultures: Democracy versus Dictatorship.  Ginn and Co., 1937.  Pages 678-9.