All the great industrial democracies of Europe are now characterised, to varying extents, by the same contradiction. Their economies require what their societies fear: the immigration of workers, especially specialised workers, in increasing numbers. The rhythms and forms of economic development in times of globalisation require the most advanced nations of Europe - where the average age is increasingly high and the birth rate increasingly low - to move rapidly on the road to a multiethnic society, to the linguistic, cultural and religious cohabitation which is undoubtedly one of the main sources of tension around Europe. Proof of this lies in the fact that the issue of immigration, and of the way to deal with the phenomenon, is one of the last remaining ideological distinctions between the left-wing and the right-wing, between "selfishness" and "solidarity".

Both horns of the dilemma correspond to objective data: the European economies need an adequate workforce to stay competitive; the old social groups are deeply disturbed at having to adapt to cohabitation with new, different and increasingly numerous immigrant groups. This explains the phenomena of incomprehension and intolerance that can lead to forms of racism and xenophobia, at times virulent, at times also organised.

The best way to manage this epoch-making change and to guard against the potential dangers is to provide all the parties involved - employers and European citizens, old and "new" - a framework of clear and applicable rules, preferably valid for the whole territory of the European Union, to give everyone concerned the security of a clear confine between legality and illegality.

All this is easier said than done. Partly because it is only recently, after waiting far too long, that the Union has decided to draw up common policies on immigration. For too long those countries with a much wider experience of the phenomenon suffered from the illusion that they could cope much better alone than with countries where immigration is more recent, such as Italy and Spain. But no national government, however efficient, is able to solve within its own national frontiers a problem that has no frontiers.

The need to arrive as quickly as possible at the definition of common European rules and the creation of the instruments necessary to apply them is made more urgent by the presence in Europe of xenophobic - openly or otherwise - political forces (also opposed- and this is no coincidence - to the process of European integration) which threaten to open up wounds in the body of the increasingly multiethnic contemporary societies, wounds which it will take a long time to heal. These forces, which gain electoral consensus by playing on the fears and doubts that immigration - especially illegal immigration - arouses in the most vulnerable sectors of society, and also by promising illusory mass expulsion of the unwanted newcomers, must be countered by policies, especially at national level, aimed at regaining the trust of each society in the ability of its administrators to deal with every type of situation.

Where do the frontiers of Europe end? Personally I do not believe very much in the so-called "natural frontiers" - the Ural Mountains, the Bosporus, and so on - whether or not they are reinforced by the history of the peoples who live on each side of these imaginary lines.

The current reality of the European Union, which has been expanding for fifty years, raises the prospect of a "new Europe" in the future: but to define a priori the geographical boundaries and the time span of this process is a risky and rather futile exercise. It would, in fact, now be necessary to take into consideration the many political and economic variables that the present and future European leaders will have to evaluate: those of the European Union itself, those of the member states and the candidate states, and also those of countries such as Russia and Ukraine which have not yet taken into consideration any form of adhesion to the European institutions.

The scenario is highly complex, but it can nevertheless be brought down to a single dilemma: either the process of European Union will find the sort of "visionary" leaders it has enjoyed in the past in order to fulfil the dream of the founding fathers, or it will be reduced, sooner or later, to a soulless association of a certain number of sovereign states. A sort of "new CSCE", as some people have defined it.