When the tax dispute surrounding the half-billion-euro stamp duty bill on AbbVie’s acquisition of Allergan became public in January, I wrote about the influence the case would have in defining the Tax Appeals Commission’s power by testing limits not explored since its establishment under 2015 legislation.  Recent judgments in separate disputes illustrate the way case law is emerging to comfort State bodies other than the courts in their role to apply rules ranging from national legislation to the Constitution and EU directives – and what they may or may not do when such rules are in conflict with each other.…