His government says these are needed to avert a U.S. invasion.[..]

This is just too funny for words. The US has no such intentions and Kimmy knows that. The Chinese and others  have no doubt told him that as well. The US does not want to create any problems with China and vice versa. Kim loves to play games and so many have allowed him to do so. WHY? The little tail wagging the big dog. China should stand up to N Korea. They too love watching N Korea irritate and jab the big elephant.

What would happen to all the people in N Korea if war broke out? Who would be responsible? ie -Influx of N Koreans to China, Reparations by the US and perhaps others.

It's a crime-the people's money that has been spent re Kim's nuclear program.