If you study North Korean history from its inception...Russia has been the main player, not China. It is the source and wellspring of North Korea’s nuclear program.
China has more money now. But both China and Russia see it in their interest that the U.S. does not have it easy.
It was years of failed U.S. policy that led to both these countries having this much leverage over the situation.
President Trump has talked to Kim Jong Un of North Korea and he’s talked to Vladimir Putin of Russia.
Lets hope the talk continues... ..