The paper discusses competing positions and arguments of main European actors in the debate on the Investment Court System (ICS). The European Commission pushes for the ICS to replace investor-state arbitration, in bilateral agreements (such as EVFTA and CETA), as well as a future multilateral solution. The ICS mechanism is meant to remedy legitimacy deficits of arbitration and to secure leading role of the EU in designing investment protection standards. Meanwhile, some of the civic society organizations see the EU law as a useful tool to oppose investment protection systems. A judicial review of CETA in Opinion 1/17 creates a possibility for arguing that ICS infringes the principles of equal access to justice and the autonomy of EU law. The Court of Justice has its own agenda in this matter as, in upholding the adjudicatory autonomy, it acts both for the preservation of its role as the ultimate umpire in the EU and, arguably, for the strengthening of the EU itself.