Common sense (which probably is not worth much when it comes to international relations) suggests that without China's aid DPRK would quickly collapse. Presuma

Common sense (which probably is not worth much when it comes to international relations) suggests that without China's aid DPRK would quickly collapse. Presumably China does not want to see this happen because re-unification with South Korea would be a possible outcome (although I suspect the South Korean economy would have trouble absorbing the North Korean population without significant aid from the US and "international community"), and that would put a strong US ally right on China's border. In my mind the only peaceful resolution to this situation is a diplomatic agreement with China, which would seem to be exceedingly difficult to achieve without a massive effort on the part of the US. Unfortunately, given the level of rancor and demagoguery against China that is showing itself in US politics at the moment, not to mention provocative actions such as the TPP and Abe's desire to change Japan's constitution to arm itself, the aforementioned peaceful outcome seems unlikely to me.