Compared with the most recent years, the European Union does not currently face a large external migration problem. What it undoubtedly faces, however, is a large internal political problem about such migration. Monthly “irregular arrivals” into the EU from the Middle East and Africa have actually fallen like a stone since 2015. In May this year they were down 96% from their October 2015 peak. Depending on events, 2018 is currently on course to see the lowest irregular migrant totals across the Mediterranean for four years.

The politics of migration are an entirely different matter. They follow a separate path. Austria and Italy have both elected hardline governments in recent months to join the eastern bloc of Poland, Hungary, the Czech Republic and Slovakia in resisting refugees and opposing any EU quota system. Germany’s coalition government is also under huge internal pressure to take a much tougher approach than in the past.

Seen from Britain, the June 2018 EU summit in Brussels was supposed to be a milestone in the Brexit process. In reality, the EU council barely debated Brexit at all. There was a brief speech on the first evening by Theresa May, and a discussion among the 27 on Friday which generated an even briefer, though notably bad-tempered, communique. The difficult Brexit issues have all been postponed. Instead, the issue that forced the 28 national leaders to argue among themselves until dawn on Friday was not Brexit, but migration.

It was very important that the EU struck its deal this week. Failure to do so would have signalled the union’s impotence in the face of external migration and of the politics that this migration has thrown up in almost every member state. It might also have brought down Angela Merkel’s government, leading to a power vacuum within the EU on the eve of Donald Trump’s hostile and troublemaking visit to Europe next month, and perhaps also triggering a domino process of national border closures that would have brought the Schengen free travel area to its knees.

Whether the deal will last, or will work, or will begin to draw the sting of the migration issue are all profoundly doubtful, however. It is very hard to be confident that any of these things will happen. The summit communique may say that the issue is one for Europe “as a whole”, but the practical reality is that differences were papered over, not resolved. The EU’s much-vaunted principles of solidarity were conspicuous by their absence in words of studied vagueness.

Crucially, the 28 were as unwilling as ever to share the impact of refugees. Italy’s demands got nowhere because of blanket central European objections (backed by Britain). Instead Italy’s grievances were ultimately bought off by a voluntary system of new “control centres” in those countries willing to allow them, in which the claims of rescued migrants would be processed. There were, though, few details and the position of humanitarian NGOs was ignored.

The response to Mrs Merkel’s insistence that all member states should commit to take “all necessary internal legislative and administrative measures” to prevent refugees from heading across internal EU borders in order to get to Germany is equally problematic. Though Greece seems willing to work with Germany on this, it is unlikely that Italy, in particular, will do what Berlin wants. Relief for the German chancellor may not last long, especially if Mr Trump, who has Germany in his sights over trade and military spending, has his way.

The leaders backed plans to put more money and resources into external border controls and agreed to create “processing centres” outside Europe. But it remains to be seen whether these commitments are bankable or effective. This was a very fractious summit on a deeply divisive issue, and it may signal a more fractious EU, not an EU that has pulled back from the brink. Italy’s attempt to block every single summit conclusion on every subject unless its migration control demands were satisfied may have gone down well among anti-migrant Lega voters back home. But it signalled that, if this is a “fortress Europe”, it is a fortress full of faultlines.