The Union is founded on the principles of liberty, democracy, respect for human rights and fundamental freedoms, and the rule of law, principles which are common to the member states. - Article 6 (1) of Treaty on European Union

When the drafters of the Amsterdam Treaty set about formulating a clause - inserted as Article 7 - that would enable the Union to suspend the rights of a member-state in "serious and persistent" breach of such fundamental values, they certainly did not have Austria in mind.

The idea was twofold: firstly, to give to what was seen as largely an economic union a political dimension based on human rights and liberal values. Secondly, although less explicitly stated in public, it was to warn the accession states that there would be no slipping back to their bad old ways once admitted.

And so the issuing to Vienna this week by its 14 EU partners of a diplomatic yellow card came as a shock to Brussels.

Although Commission President Romano Prodi had detailed foreknowledge, even the ambassadors of the member-states, and in some cases their foreign ministries back home, were kept in the dark until after the deed was done. Diplomats and officials have been wandering around in a daze ever since muttering "this is what happens when prime ministers take it upon themselves to make foreign policy". Even MEPs have been only cautiously supportive. Of course, once it was done there had to be a rallying round in support of the heads of government.

The Commission, when it met on Tuesday morning in emergency session, was gloomy. Sources say most of those who spoke said that although the prospect of a far-right role in the Austrian government was deeply worrying, they thought the Portuguese initiative was a mistake - but it had to be backed and the Commission did so as far as its legal role would permit.

As guardian of the treaty and of the rule of law in the EU, the Commission could not deny any member-state its treaty-based rights to attend and participate at meetings, but could signal its support by drawing attention to Article 7. Prodi and the Portuguese Prime Minister Antonio Gutteres were agreed - the gesture had to be made by the member-states intergovernmentally without implicating the workings of the EU institutions.

Yet, although the bilateral boycott should not in theory impinge on the EU's multilateral contacts, of course the institutions will be affected. There is a vagueness about where bilateral relations begin and multilateral ones end. Relations will be soured, routine communications will be impaired, negotiations on simple matters prolonged.

And France, the driving force of the initiative, has made a stick to beat its own back in promising the Austrians a rough time during its six-month presidency from June. Senior Commission officials are asking rhetorically who, more than anyone, wants to see the Inter-Governmental Conference on treaty reform finished by December? The answer is President Jacques Chirac. Yet Vienna retains its veto.

In the ranks of the 14 there is growing unease at having been bounced into signing up to the boycott. British Prime Minister Tony Blair has been singularly silent on the issue, reflecting serious diplomatic concerns about the political effects of the move in Austria. In Eurosceptic Denmark and Sweden the "bullying" attitude of the 14 is playing into the debate on whether to sign up to the euro, providing strong ammunition for the No campaigns. In the Finnish presidential election, an embarrassed Tarja Halonen, until recently foreign minister, has been forced to defend it against her conservative opponent in a tight-fought contest.

The view in Brussels is that the ill-thought-out move by the 14 owes more to domestic considerations in a number of memberstates than to any genuine collective outrage at Haider. Mr Chirac, furious at the abuse hurled at him by Mr Haider, is also deeply preoccupied by the role of the National Front in France, as is Guy Verhofstadt, Belgium's Liberal Prime Minister, with Vlams Blok on his doorstep. In each country the refusal to co-operate in government or public administration with such forces marks a key dividing line between parties on the right.

In Germany, the Social Democratic Chancellor Gerhardt Schroder is understood to be deeply worried that the current disgracing of the conservative opposition CDU will see its vote move to the far right. Hence, a desire to see the latter exposed as international pariahs.

There is also concern here about an exit strategy. Because Austria is being punished - not for any crime it has yet committed but for forming a government - must diplomatic isolation necessarily last while that government is in place?

Four years or more? And what happens when Vienna's turn comes around again for the EU presidency? Or what about its chairmanship, due to start soon, of the Organisation for Co-operation and Security in Europe? That there should even be talk of the need for an exit stratgey reflects the reality that no one believes there is likely to be any possibility - let alone desirability - of the more radical action envisaged in Article 7.

A suspension of any of Austria's rights as a member would require first a unanimous finding by heads of government, backed by a majority in the European Parliament, of a "serious and persistent" breach of Article 6(1). What member-states wanted this week was not radical surgery, but the lancing of a boil. The trouble is that in lancing Haider's poison with the imperfect, clumsy instruments they have chosen the infection may well be spread.