"This guy, he's like a maniac, OK? He wiped out the uncle. He wiped out this one, that one. I mean, this guy doesn't play games. And we can't play games with him. Because he really does have missiles. And he really does have nukes."

So spoke U.S. President Donald Trump in Iowa in January. North Korea flight-tested a ballistic missile on Sunday that landed off Japan's west coast, so what will he do now? What can he do? And is North Korea's 33-year-old dictator, Kim Jong Un, really a maniac?

South Korea's foreign ministry certainly thinks so: "North Korea's repeated provocations show the Kim Jong Un regime's nature of irrationality, maniacally obsessed in its nuclear and missile development." The same word was used a great deal after North Korea tested nuclear weapons in January and September of last year.