Torben Spaak (Stockholm University) has posted A Challenge to Bix's Interpretation of Kelsen and Hart's Views of the Normativity of Law (Revus Journal for Constitutional Theory and Philosophy of Law, 2019, DOI/0.4000/revus.4561) on SSRN. Here is the abstract:
Brian Bix discusses questions of legal normativity, arguing (1) that Hans Kelsen’s theory of the basic norm is best understood as saying that a person may choose to presuppose the basic norm in order to interpret the actions of legal officials normatively; (2) that H. L. A. Hart is best understood as espousing a sui generis view of legal normativity; and (3) that Hart’s view is preferable to the rather popular view that law makes some sort of moral claim. I accept (1) but think it is rather trivial, I find (2) plausible but the view itself problematic, and I am therefore skeptical of (3).