Professor Paul Craig of Oxford University has written a short article that really needed writing. It is entitled "Competence and Member State Autonomy: Causality, Consequence and Legitimacy".
You can download it on SSRN here.
The article is very clearly written and deals, amongst other things, with the claim that the Court of Justice is primarily responsible for the enormous expansion of the power of the European institutions and the reduction of the autonomy of member States in the face of ever encroaching and developing EU law.
Here's what the abstract says:
"The scope of EU competence and the limits on Member State autonomy can validly be analyzed from a variety of perspectives. This chapter considers one such perspective, the prevailing concern about the scope and exercise of EU competence. This concern is often based on the premise that some reified entity called the EU has increasingly arrogated power, with a consequent diminution of national autonomy that the Member States have been unable to resist, and the ECJ is frequently regarded as bearing primary responsibility. It will however be argued in the first half of this chapter that the Community courts were but one factor out of four responsible for the expansion of EU power over time, and that the Member States themselves were equally important. This in turn raises interesting questions as to why Member States accepted and contributed to the expansion of EU competence, which is addressed in the second half of the chapter."
Of course, a simple point could also be made: Whatever the Court of Justice does, the member States can always undo in a Treaty revision or protocol. And they have hardly ever overruled the Court's case law in that way.