This paper offers an analysis of the authoritatively normative concept PRACTICAL OUGHT that appeals to the constitutive norms for the activity of non-arbitrary selection. I argue that this analysis permits an attractive and substantive explanation of what the distinctive normative authority of this concept amounts to. I contrast my account with more familiar constitutivist theories, and briefly show how it answers ‘schmagency’-style objections to constitutivist explanations of normativity. Finally, I explain how the account offered here can be used to help (...) realists, error theorist, and fictionalists address central challenges to their views. (shrink)