A normative domain is a realm of action or thought in which it's necessary to invoke the concepts of requirement/obligation, permission or prohibition. Closely associated with these is that of correctness. A rule of grammar, as this term is traditionally understood (e.g., the requirement that determiners precede the nouns with which they are associated) is accordingly normative in nature. This chapter explores some of the consequences of this fact, including: the relationship between the notions of rule and constraint; broad-vs. narrow-scope rules; and ascription of different kinds of ill-formedness to ungrammatical examples. Some attention is also given to the critique of grammaticality-based and intuition-grounded linguistic practice advanced by Sampson and Babarczy (2013), and motivation is offered for a warmer embrace of traditional grammar than is customary among linguists.