Most analysts agree some immigration is healthy
The rise of far right-wing political formations like the National Front in France and similar parties in Belgium, Holland and elsewhere is frequently linked to the issue of immigration.
Such parties themselves see a strident anti-immigrant message as central to their appeal.
But the issues raised by immigration are complex and immigrants may indeed be essential to the future economic success of many European countries.
For Jean-Marie Le Pen, the leader of the French far-right National Front party, and indeed for many similar formations elsewhere in Europe, the cause of socio-economic problems is simple.
It is summed up in one word: immigration.
Immigrants, according to the far right, cause crime and delinquency; they over-burden the social welfare system and they take the jobs of solid white citizens.
Deal with immigration, says the far right, and many of Europe's social problems will be solved.
'Simplistic remedies'
Quite what is meant by the term "immigrant" in their vocabulary is far from clear.
Many so-called immigrants in Mr Le Pen's terms may well have been born in France.
But they are often black or brown-skinned; north African or Asian.
And many are Muslims - a community that the far right generally sees as impossible to assimilate into what they regard as a dominant white culture.
The problem for the simplistic remedies of the far right is that their arguments - while appealing to many ordinary voters - are simply wrong.
Most experts recognise that European Union countries need immigrants to maintain a healthy economy.
Falling birth-rates
European populations are ageing.
Elderly people made up some 13% of the population in 1975 and could be as many as 22% by 2025. Birth-rates in European countries are falling.
All this means that the only way that the working population can be maintained, let alone expanded, is through immigration
Clearly illegal immigration remains a problem.
Cultural differences cannot always easily be reconciled.
But according to many experts the rise of the far right rests upon a fundamental paradox: immigration, far from destroying European societies, could ultimately be their saviour.