A North Korean government collapse would have serious consequences in North Korea and beyond. At the very least, a collapse would reduce the already scarce food and essential goods available to the population, in part due to hoarding and increasing costs. This could lead to a humanitarian disaster. Factions emerging after a collapse could plunge the country into civil war that spills over into neighboring countries. Weapons of mass destruction (WMD) could be used and even proliferated. This report examines ways of controlling and mitigating the consequences, recognizing that the Republic of Korea (ROK) and its U.S. ally will almost certainly need to intervene militarily in the North, likely seeking Korean unification as the ultimate outcome. But such an intervention requires serious preparation. North Koreans must be convinced that they will be treated well and could actually have better lives after unification. The allies need to prepare to deliver humanitarian aid in the North, stop conflict, demilitarize the North Korean military and security services over time, and secure and eventually eliminate North Korean WMD. Potential Chinese intervention must be addressed, ideally leading to cooperation with ROK and U.S. forces. Plans are needed for liberating North Korean political prisons before the guards execute the prisoners. Property rights need to be addressed. The ROK must sustain its military capabilities despite major reductions in force size due to very low birthrates. And ROK reluctance to broadly address North Korean collapse must be overcome so that plans in these areas can move forward.