The present paper proposes a structural operational semantics and the related semantics for normative systems. The proposed approach focuses on explicitly representing in force obligations and violations as events in a temporal framework, determining the state of a normative system. In the paper we use a set of core principles, defining some of the properties required when reasoning about norms, to motivate the semantics of the approach. Finally, we show that the proposed approach is capable of reasoning about more complex legal scenarios.