FOR THE past year excessive sovereign debt has endangered the European project. For the coming year it may be north African boat people who present the greatest danger to European unity.

The turmoil over illegal migrants is a consequence of the Arab pro-democracy awakening on the far side of the Mediterranean and, perhaps, of the Western military intervention in Libya. According to UNHCR, more than 20,000 boat people have landed on the Italian island of Lampedusa this year, almost all of them from Tunisia. More than 800 have arrived in Malta, mostly from Libya.

At today's meeting of the European Union's interior ministers in Luxembourg, Italy and Malta called on the EU to activate a 2001 directive to grant temporary protection to migrants in cases of “mass influx” and to share the burden of absorbing the newcomers. But ministers flatly turned down the proposal. The European Commission described the call as “premature”, but said the EU was offering “solidarity” in other ways, including money and additional surveillance teams provided by the EU's Frontex border agency.

Malta would be helped on a voluntary basis in resettling boat people, given its small size and the fact that most of its newcomers are people fleeing war in Libya. Italy is confronted by a bigger wave, but its boat people are mainly economic migrants rather than refugees who have taken to the sea because of the economic crisis in Tunisia after its pro-democracy revolution, and because border controls have become laxer after the downfall of President Zine el-Abidine Ben Ali.

In any case, say fellow ministers, the flow of migrants to Italy is nothing like the influx of refugees into Europe (mainly Germany) during the Balkan wars, in response to which the EU directive was adopted.

Nonetheless, Roberto Maroni, the Italian interior minister, complained bitterly that the EU had abandoned Italy (video here, in Italian). “I ask myself if it makes sense to continue in this position: of continuing to be part of the European Union, an institution that is activated immediately to save banks, to declare war—but when it is a matter of expressing solidarity with a country in difficulty, such as Italy, it hides.”

He said that his country had been told: “Dear Italy. It's your business. Manage it on your own.” If this is the attitude of the EU, he declared, “we are better off alone than in bad company.”

Such comments are not entirely unexpected from a leading member of the anti-immigrant and Eurosceptic Northern League, except that Silvio Berlusconi, the Italian prime minister, had offered similar sentiments a day earlier during a visit to Lampedusa: “Either Europe is something concrete, or it would be best to part ways”.

Nobody expects Italy, a founding member of the EU, to begin proceedings to withdraw. Its lashing out at outside foes may be a sign of a political system that is in fibrillation because of the multiple legal cases against Mr Berlusconi (he was in court today, denouncing "leftist" magistrates). Yet the anti-Europe mood has been harsh enough to alarm President Giorgio Napolitano (report here, in Italian).

Italy is resorting to a ruse that other countries suspect is a blatant attempt to export its problem: granting all arrivals from Tunisia temporary protection in Italy. In theory this would allow them to travel freely throughout the passport-free Schengen area, and most can be expected to take the opportunity to slip across the Alps to other countries, above all to France.

Over the weekend, the Italian finance minister, Giulio Tremonti, seemed to issue a veiled warning: “A cheque that needs to be honoured has arrived in Italy, but it will not stop in Lampedusa. It will arrive in Germany, in the north and all over Europe.”

French authorities have already stepped up identity checks in areas near the border with Italy. ClaudeGuéant, the French interior minister, said about 2,800 Tunisians had been caught so far in the past month, of whom about 1,700 have been expelled back to Italy. He and Mr Maroni met last week to smoothe over their row over the handling of migrants, agreeing to conduct more joint patrols in the Mediterranean.

But Mr Guéant would not yield on the substance of the disagreement. Italy had a right to issue temporary permits, he said; France had a right to check whether Tunisians arriving from Italy had a proper passport as well as funds to support themselves, as stipulated under Schengen rules. Every country in Schengen had to bear its responsibilities, he said. Italy was not the only country with a migration problem: France had to contend with thousands of illegal Afghan and Pakistani migrants who congregate around Calais to try to slip across the Channel to Britain.

Others have been more openly critical of Italy. “I was quite dissatisfied with Italy's surprise decision to pass on its problems to all the others without prior notice,” said Gerd Leers, the Dutch minister for immigration and asylum. Austria's interior minister, Maria Fekter, said her country would investigate means of stopping migrants from crossing its borders. Similarly, the German states of Bavaria and Hesse said they might introduce border checks.

Migration is likely to be a contentious issue at June's European summit (see this paper by the Centre for European Reform). With anti-immigrant parties on the rise across Europe, the dispute has great potential to degenerate.

Like the euro, which requires mutual trust among members about their readiness to preserve sound public finances, the Schengen area relies on mutual trust about the capacity of members to control their borders and migration flows. But Italy threatens all that: rather than acting as a dam and reservoir for migrants, it would rather be a weir, allowing the human flow to pass over it.

In the euro crisis, creditors and debtors alike wondered whether they would be better off without the other. Now it is the countries of the Schengen borderless travel area that are starting to question another of Europe's great integration projects.