The North Koreans actually have this in common with Trump, who also likes to use threats to walk away as a negotiating tactic. Many years ago Trump reportedly tried to get the George H.W. Bush administration to send him to negotiate arms control with the Soviet Union, saying that his brilliant tactic would be to welcome the Soviet delegation, then shout “F––– you!” and leave the room. The Bush administration for some reason felt that sensitive negotiations should be done by experienced diplomats and not blowhard real-estate developers, so it declined his help.