Proactive implementation of trade agreements?

ASIL Insights has an interesting review of a case of the Court of Justice of the European Union (CJEU) relating to Hungary. The CJEU in Commission vs.Hungary held that a Hungarian law which mandated an international agreement to be entered into by a foreign university (Central European University) violated the national treatment obligations of Hungary under the General Agreement on Services (GATS) under WTO.

Two interesting analysis on the judgement concerning the applicability of GATS by CJEU and the domains of the European Commission and Member States with respective to their competencies is found here and here.

What I found striking about this judgement is that the European Commission challenging one of the Member State's (Hungary) action as being WTO inconsistent. In normal circumstances, a WTO member where the foreign university originates or is registered (in this case the United States) could have filed a case in the WTO against the European Union. However, here the Commission brought a case against Hungary in the CJEU.

Proactive implementation of trade agreements? Imagine a large federal country where the cetral/federal government brings a case against one of its states/provinces for a measure which is apparently inconsistent with WTO law? Pre-empting WTO dispute settlement may be?