No secular organization has ever peacefully deprived states of as much sovereignty as has the European Union. National autonomy to regulate the environment, labor, the professions, antitrust, consumer protection, food and product safety, agriculture, advertising and almost any other area one can think of, even highly sensitive ones such as criminal law and civil procedure, has been gradually constrained over the years by rules coming from the EU.
Often the source of these rules is EU legislation, usually in the form of directives, which are laws that contain instructions to the member states to take certain action or implement certain rules. Such directives are often controversial because they are adopted by majority voting in the European Parliament and the European Council, meaning that states may well have measures imposed on them that they did not support. The directives also often lack public support because they originate in relatively distant EU institutions and come into being in a way that does not involve national parliaments, which are still the legislators with the most public acceptance and respect.
Yet despite all this, there is usually a grudging acceptance of EU legislation, which does at least emerge from a process in which elected parliamentarians, in the European Parliament, and national ministers, in the European Council, play a key role. By contrast, the decisions of the European Court of Justice are sometimes met with a degree of shock and disbelief. In the past five decades the European Court of Justice has been the most powerful and influential supreme court on the planet, playing a central role in creating the EU legal system and giving it teeth, and it has done this on the basis of a rather freewheeling and goal-oriented judicial style that is quite alien to most European legal systems.