LONDON — The enlargement of the European Union, with the addition of up to 10 more states and dozens of new local cultures and minorities, is approaching.

But with it comes a renewed fear about large-scale migrations and the threat of social disruption and tensions. Few issues now raise as much emotion and intensity of feeling as the “threat” of invasion by foreigners. Evidence of this can be spotted in the increasingly shrill tone of politics in countries like Austria, which sees itself as especially exposed to migration from the east. Meanwhile, the applicant states of central Europe worry about a Slavic influx from the former Soviet bloc countries that lie beyond what will be the EU’s new eastern border.

In Western Europe, both Britain and France have experienced sharp rises in immigration flows, admittedly not so much from Eastern Europe as from the Indian subcontinent, North Africa, the Middle East and the Caribbean. But the pressures are enough to arouse general fears that EU enlargement will open more doors to immigrants in all shapes and sizes, some seeking work, some claiming refuge from political harassment (asylum-seekers) and some just slipping in clandestinely and then vanishing into the domestic scene to work illegally or engage in criminal operations.

Add to this the present concern about terrorists infiltrating societies, concealed in the broader immigrant flow, and the demand for the politicians to install far tougher external controls and build new walls to keep the intruders out are becoming irresistible.

Whether the actual facts of population movements justify the public mood of extreme apprehension is debatable. East-west migration in Europe has so far been modest, despite the contrast between rich Western markets and the impoverishment of the former communist east. Europeans seem historically reluctant to move very far from their home villages and towns.

But the feelings are real enough. On the whole, Britain, which has the largest foreign population and labor force in Western Europe (at about 4 percent), has coped fairly well with the newcomers. The crucial balance in the immigrant equation — between ensuring that the new arrivals “fit in” and contribute to their adopted home, on the one hand, and tolerating the unfamiliar ways of new ethnic minorities, on the other — has been reasonably well managed.

But lately this balance has begun to wobble, with a number of events leading to some basic rethinking about how a modern society that, like Japan, was traditionally both homogeneous and possessing a strong sense of identity and history, adjusts to the reality of large-scale immigration.

First, in addition to the omnipresent terrorism fear, there have been outbreaks of urban unrest with strong racial overtones — mainly in the less prosperous northern textile cities that attracted large immigrant inflows in the postwar period.

Second, there has been a sharpening perception that immigration is adding to the enormous pressure on housing and social services, particularly in crowded southern England. Finally, as the number of asylum-seekers has soared, tripling in the last 10 years, a view has grown that many of these refugees are in fact really economic migrants attracted to Britain by the rumored ease with which welfare benefits are paid out, by the lack of identity document requirements and by the not unflattering belief that the British treat their immigrants more gently and justly than many other countries.

Faced with these growing anxieties, government attitudes have begun to change. The question is how to restore the balance between tolerance of newcomers and their measured integration into British society. Most people accept — except on the political far right — that some immigration has to take place and that, properly handled, it can be both stimulative and beneficial to the economy and society. Skilled immigrants, especially with technical qualifications, continue to be welcomed and allowed to work, although often for only a limited period.

But the new thought is that much more can be done to turn those who are finally allowed to settle in Britain into full and effective citizens rather than let them remain as excluded and disaffected members of ethnic minorities who feel they are being discriminated against. Merely asserting that British society has become “multicultural” is not enough — and may make matters worse.

The word “assimilation,” previously frowned on, is beginning to be used and policies are now much more aimed at ensuring that new arrivals learn proper English, take an oath of allegiance to their new country, respect national symbols and generally adapt and become good citizens.

Fresh and coordinated efforts are being made to screen, and if necessary turn away, immigrants at the outer borders of the European Union, before they get inside the EU area and are shuttled from country to country, often ending up, yet again, in Britain.

None of this will solve the immigrant issue as it is now developing. We live in an age of large-scale migration that nations are powerless to completely halt even if they wanted to. But at least the point is now being appreciated that if a society is to be tolerant and fair to immigrants then it must not feel its identity and cohesion are somehow being eroded.

On the contrary, a strong and confident sense of national identity and history goes hand in hand with an open embrace of newcomers. We wish others to join us, but we also wish to keep and enhance our own ways and our own culture. What could be more reasonable than that?

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