How to deal with North Korea is one of the key international security challenges the world is facing today. Since Kim Jong-un succeeded his father as supreme leader in 2011, the country has conducted several ballistic missile and nuclear tests, severely raising tensions on the Korean peninsula and beyond.US President Donald Trump issued a sharp warning to Mr. Kim at this year’s UN General Assembly. If the US was “forced to defend itself or its allies, we will have no choice but to totally destroy North Korea. Rocket Man is on a suicide mission for himself and for his regime,” the president told world leaders. Ever since taking office earlier this year, Mr. Trump has taken a tough line on North Korea, also pushing other countries, first and foremost China, to do more to counter Pyongyang.