This article presents a reliability, resiliency and adaptability policy framework for power systems. Our proposed broad framework enables a cost-effectiveness analysis of reliability, resiliency and adaptability by incorporating the entire power system into the analysis, including common-cause failures, characterizing outages in a detailed manner, enhancing the concept of the loss of load probability, considering social costs beyond economic ones, and explicitly assessing the probability that the supply-demand mechanism succeeds. Our framework is applicable to all types of power systems, including those with liberalized wholesale electricity markets, or those with high levels of variable renewable energy. In the context of liberalized power systems, our analysis shows that it is necessary to consider explicitly the probability that the real-time energy market clears.