One remarkable feature about the EU is the degree to which national governments of the member states obey it almost without question. Ordered by the European Court of Justice to hand over large sums of their taxpayers' money to Brussels as a fine for some technical infringement of the EU treaties, they do so like lambs and virtually without question. This apparent vindication of the moral authority of the EU may, however, soon be put to the test.

The test bed, as you might have imagined, is Poland. Its ruling Law and Justice Party, Eurosceptic to the core save for its liking of EU handouts, has long been a thorn in the side of the EU Commission. Recently, the Polish government introduced a law to reduce the retirement age of its Supreme Court judges, applicable to those already in post as well as those appointed in future.Judges already above 65 would be able to ask the President for extension, but would have no right to it. According to the government, this is aimed at removing remnants of the Communist regime. For its opponents, it is directed at elbowing aside those judges unwilling to act as the government's poodles. The matter has split the country, not helped by an alleged ignoring by the government of an order from the Supreme Court not to interfere with its composition.

Whoever is right, the EU has seized upon this as a possible means of bringing Poland to heel.For in the EU's eyes, Poland has been unacceptably lukewarm over a number of other matters, such as immigration.

Under Article 7, a four-fifths majority of the European parliament could find a severe breach of the values of human dignity, freedom, democracy, equality, the rule of law and respect for human rights, and, if so, recommend steps to withdraw a member state's voting rights. Unfortunately, in the case of Poland, this would be unlikely to succeed, since the sanction can only be imposed by a vote of all member states, and Hungary, a state in much the same position as Poland, has said it will veto it (a favour which, not surprisingly, Poland has promised to return to Hungary should it face the same prospect).

This has left the Commission in difficulties. Having taken purely symbolic steps such as procuring the expulsion of the Polish judicial organisation from the vapid talking-shop known as the European Network of Judiciary Councils, it has now gone to law big-time. It has asked the European Court of Justice to declare that the new Polish law is in breach of the EU treaties, and in addition, while the wheels of justice grind (and they can grind remarkably slowly in Europe) to order the Polish government to dis-apply it in the interim.

For all the suave assurances from the EU Commission that it is merely acting to preserve democracy, this move looks like a very considerable upping of the stakes; possibly, indeed, a move of desperation. There are a number or reasons for saying this.

First, while the Commission has a good deal of face to lose if this move fails, the legal support is by no means certain. It is based on the requirement for a "fair hearing" under the Charter of Fundamental Rights, and also on the need for member states to "ensure effective legal protection" of EU rights; the latter on the rather tendentious argument that, because national courts might have to apply EU law, they must have a degree of independence. Whether these arguments will succeed is highly uncertain (the case-law is, to say the least, confused).

Secondly, even if the Commission is right (and we will not know that for some time), the idea that EU law apparently gives the European Commission a kind of roving commission to dictate and litigate over the judicial appointment and retirement process in every court from Talinn to Tarragona, and from Lisbon to Ljubljana, has its own problems. It is likely to raise eyebrows and hackles in any country where people watch the Europeanisation of more and more matters that had previously been regarded as a national prerogative.

Furthermore, the issue will be made even more controversial if the ECJ goes further and orders, as an interim measure, the immediate suspension of a law passed by the Polish democratic legislature just in case it (the ECJ) later finds that there has been an infringement of EU law.

Thirdly, there is every possibility that Poland, in contrast perhaps to other EU member states, would not agree to such an order by the European Court of Justice. Indeed, all the indications are that the Polish government will take the view that the composition of its Supreme Court is a matter for it alone and no business of the European Union. And, should the ECJ decide otherwise, the Polish government will simply ignore its orders.

Should this happen, the EU would be plunged into a serious crisis. The EU is not yet a body quite like the US with a National Guard to send in to impose its law on the recalcitrant. Faced with a Poland that simply refused to obey its court or pay any fines, the EU could do little apart from, perhaps, withdrawing its own payments; a quixotic gesture that would, one suspects, only pour petrol on the smouldering embers of resentment and possibly even precipitate a Polexit.

The power of the EU today is rather like that of the erstwhile British Raj in India: built largely on bluster and habit. With only 50,000 troops managing 350 million people, the Raj made the system work for as long as it did by picking its quarrels carefully. The EU, with less hard power needs to bluff more to maintain its ascendancy but doesn't seem to have taken this to heart.

There may be important matters to take a stand on with regard to member states but an argument over the technical composition of their Supreme Courts is not one of them. It is still early days, but events in Poland may well presage more shocks and drastic developments on the EU front.