The problem is that from what I can tell (which of course is next to nothing, though apparently even our intelligence agencies have limited information due to the limited nature of the internet there and a dearth of human assets on the ground), those people who acted as pro-China advocates in North Korea are being executed (in some cases, by anti-aircraft shells), which means the regime is less likely to listen to China, though the recent refusal by China to buy North Korean coal might force Fat Kim to start listening more closely.

However, I don't think that China is in control the way it used to be. This is bad for everyone because as long as China was keeping North Korea in check, it was China's answer to US support for Taiwan. Now, China will have to decide if it wants to (a) invade North Korea directly or overthrow Kim (if possible) with a pro-China coup, (b) let the US and South Korea fight the North, or (c) risk a direct US-China confrontation by continuing to support the North.

The latest assessments I read were that North Korea will likely have a weaponized nuclear delivery system by the end of the calendar year. That means that from our perspective, we need to either (a) take out North Korea, (b) find a diplomatic solution or (c) force China to take out North Korea. We are not going to be able to just let the situation progress at that point because the stakes will get too high for us.

From China's perspective, each of its options is bad. Invading the North would be costly in terms of human life and have no real benefit for China, other than saddling it with a piss-poor province (which it currently has, but only indirectly). Letting the US fight the North would see US troops stationed on China's border. Risking a direct confrontation with the US is a lose-lose situation for everyone.

From our perspective, forcing China to take out North Korea would be the ideal outcome, because it would involve little or no loss of life (assuming the North didn't shell the South just for the hell of it while being invaded from the other direction). A diplomatic solution is near impossible given the North's history of ignoring its promises. Fighting the North would lead to high casualties. However, if the option is some casualties in a brief war now, or millions later if the North actually succeeds in developing a weaponized delivery system, at some point we're going to have to pull the trigger and hit them hard, fast and with overwhelming force.

That is, of course, unless we can agree with China for China to do that.