>China could presumably influence to NK to not launch missiles at neighbors.
Very questionable. If you read about the Rangoon bombing[0] the short of it is the Chinese passed on a note from the NKs to the Americans requesting trilateral talks, essentially vouching for them, just prior to the bombing. Apparently, Deng Xaiping said afterwards he'd never let 'that motherfucker' (Kim Jong Il) set foot on chinese soil as long as he lived, and apparently, KJI never did.
Very questionable. If you read about the Rangoon bombing[0] the short of it is the Chinese passed on a note from the NKs to the Americans requesting trilateral talks, essentially vouching for them, just prior to the bombing. Apparently, Deng Xaiping said afterwards he'd never let 'that motherfucker' (Kim Jong Il) set foot on chinese soil as long as he lived, and apparently, KJI never did.
[0]: https://en.wikipedia.org/wiki/Rangoon_bombing