All the elements of the North Korean nuclear crisis — the relentless drive by Kim Jong-un to assemble an arsenal, the propaganda and deception swirling around his progress, the hints of a covert war by the United States to undermine the effort, rather than be forced into open confrontation — were on vivid display this weekend. There was the parade in Pyongyang’s main square,

with wave after wave of missiles atop mobile launchers, intended to convey a sense that Mr. Kim’s program is unstoppable. Then came another embarrassing setback, a missile test that failed seconds after liftoff, the same pattern seen in a surprising number of launches since President Barack Obama ordered stepped-up cyber- and electronic-warfare attacks in early 2014. Finally, there was the test that did not happen, at least yet — a sixth nuclear explosion. It is primed and ready to go, satellite images show. READ MORE