Today's AI applications are so successful that they inspire renewed concerns about AI systems becoming ever more powerful. Addressing these concerns requires AI systems that are designed as ethical systems, in the sense that their choices are context-dependent, value-guided and rule-following. It is shown how techniques connecting qualitative and quantitative primitives recently developed for evidential argumentation in the law can be used for the design of such ethical systems. In this way, AI and Law techniques are extended to the theoretical understanding of intelligent systems guided by embedded values.