This week U.S. President Donald Trump is visiting the leaders of Japan, South Korea and China, and the same topic will dominate all three conversations: North Korea. As was the case with Prime Minister Shinzo Abe on Monday, South Korea's President Moon Jae-in will be looking for reassurance that the United States will protect his country from North Korea's nuclear weapons, but in Beijing Trump will be the supplicant.
Trump will be asking Chinese President Xi Jinping to do something, anything, to make North Korea to stop testing nuclear weapons and intercontinental ballistic missiles Trump has painted himself into a corner with his tongue, but even he knows (or at least has been told many times by his military advisers) that there is no military solution to this problem that does not involve a major war, and probably a local nuclear war.
Trump promised that North Korea would never be able to strike the U.S. with nuclear weapons, and the reality is that it will get there quite soon (if it is not already there). The U.S. has no leverage over North Korea except the threat of war, so he needs China to get him off the hook.