The first sign that Matteo Salvini was destined to do battle with Emmanuel Macron came in June, a few days after he was named Italy’s interior minister. Salvini, whose party, the League, wants to cut immigration drastically, announced that a German-registered rescue ship carrying 629 aspiring migrants from Africa would not be allowed to dock in Sicily.

Macron reacted with disgust. ‘The policy of the Italian government,’ a spokesman for his political movement announced, ‘is nauseating.’ Salvini responded that if the French wanted to show their open--heartedness, they might make good on their unfulfilled pledge to feed and shelter some of the 100,000 African migrants Italy had until recently been receiving each year.

This week, what had seemed like a personal antipathy between the two men revealed itself as an all-out battle for European hearts and minds. When Libyan rebels attacked government positions in Tripoli, threatening the agreements Italy has made with the Libyan coast guard to limit departures of migrants from the shores of North Africa, Salvini mused aloud to reporters. ‘There’s someone behind this,’ he said. ‘Someone who started a war [in 2011] that should never have been started, someone who calls for elections without sounding out his allies and the people on the ground, someone who tries to force the issue by exporting democracy, which never works.’ He urged journalists eager to know what he meant by that to ‘ask Paris’.

Days earlier, Salvini had invited the Hungarian prime minister Viktor Orbán to Milan to issue a manifesto. It was Orbán who exhorted Europe to harden its borders during the great overland migration from war-torn Syria and points east in 2015. Standing under the awning of a pizzeria in Milan, Orbán singled out Salvini as ‘my hero and my comrade in destiny’. And he singled out Macron as his nemesis. ‘There are two camps in Europe,’ Orbán said, ‘and one is headed by Macron. He is at the head of the political forces supporting immigration. On the other hand, we want to stop illegal immigration.’

Orbán is right. Salvini’s nationalism and Macron’s globalism are the two competing visions of Europe’s future. A year ago, it appeared that the newly elected French president might inherit Angela Merkel’s mantle as Europe’s unifier. He would give a new élan to a European Union demoralised by Britain’s threatened departure. It even seemed possible that Donald Trump’s episodes of boorishness might discredit the cause of immigration control in Europe altogether.

But voters have not forgiven their leaders’ opening of the immigration floodgates in 2015. Border-defending governments have come to power in Italy, Austria and the Czech Republic, and Trump’s quondam adviser Steve Bannon is now working to foster co-operation between nationalist movements, including Salvini’s, in the run-up to next May’s European elections. Much as prisons can be places where convicts hone their criminal skills, the EU Parliament has become a clearing house for Euro--scepticism, even with Ukip due to depart the scene. Salvini envisions a ‘league of Leagues’ sitting in Brussels.

Who can Macron rally against them? Even the European left is showing signs of questioning its commitment to open borders. In Germany, the Marxist Sahra Wagenknecht of the Left party has started Aufstehen, a popular front meant to woo back working-class voters turned off by the globalist dogmas, including free-and-easy immigration. Denmark’s Social Democrats have rallied behind a stern plan to impose on migrants the Danish language and Danish values. Their counterparts in Sweden, who admitted a quarter of a million migrants over two years after 2015, have recanted, tightening asylum policies in the run-up to this weekend’s nationwide elections. The nationalistic and bluntly anti-immigration Sweden Democrats are set to make big gains nonetheless.

Salvini is picking up momentum. The coalition government that his League formed with the antic Five Star Movement has won the allegiance of more than half of Italians, doubling the League’s support from 17 to 32 per cent since the spring and turning it into Italy’s most popular party.

Macron, meanwhile, has had a bad summer. It began with a scandal involving his 26-year-old bodyguard (and skiing and bicycling companion) Alexandre Benalla, who seemed to have a taste for wreaking physical violence on people who disagreed with his boss. At a May Day demonstration Benalla was captured on mobile-phone videos wearing a police helmet (although he was not a policeman), pulling one protester across the Place de la Contrescarpe by her neck, and then cold-cocking another as he struggled on the ground. In the ensuing uproar over why Benalla had barely been disciplined, Macron was reduced to telling reporters that Benalla was not his lover. Macron’s summer ended with the dramatic resignation on national radio of the charismatic environment minister, Nicolas Hulot, who explained, ‘I don’t want to lie to myself any more.’ Macron’s popularity, which has been falling for more than a year, now stands at 34 per cent. ‘Macron’s main opponent,’ Salvini jibed, ‘is the French people.’

The spectacle of two men who had never sought office becoming heads of major states on their first try — Donald Trump in 2016 and Macron the year after — may have led some people to assume that all one needs for success in politics is a ‘knack’ for it. On the contrary, making it as a politician requires mastering a lot of arcana. Trump’s enemies have been able to use their understanding — and his ignorance — of American government procedure to tie his whole presidency up in an investigative knot from which it will not soon escape. Late in Silvio Berlusconi’s career as Italy’s premier, his opponents were able to do the same, and Salvini’s foes hope to repeat the trick. In August, after Salvini refused for ten days to allow migrants on a rescue boat docked in Catania to disembark, a magistrate in Agrigento moved to charge him with kidnapping.

Salvini is an extraordinary politician. Macron is not, or at least not yet. Politics requires a patient training in discernment, something that Macron, though he is a fast learner, has not had the time to acquire. Macron has dismissed Salvini as someone who is always trying to be provocative, without considering why a politician might want to be provocative. Salvini’s most notorious remark in the days after he came to power was that, for migrants, la pacchia è finita — roughly: ‘The party’s over.’ This may be an appalling way to describe the lot of people who have risked death from thirst in the Sahara and death from drowning in the Mediterranean, but in the eyes of voters it hurt Salvini’s detractors much more, because it goaded them into inveighing against any immigration restrictions at all.

Salvini can tell an impregnable position from a vulnerable one. The French president is still learning. Every boat that appears on the southern horizon casts a sinister shadow on Macron’s invocations of European solidarity. ‘There is no such thing as a real Dane,’ Macron mused, on a recent trip to Copenhagen. Surely that not only irked Danes, but also scared some of Macron’s own voters.

Just as immigration begets immigration, populism begets populism. When nationalist parties enter parliaments, the issues they raise there change the whole context of political discussion. Almut Möller, a policy analyst at the European Council on Foreign Relations in Berlin, astutely told Le Monde: ‘Paris underestimated what it would mean when Alternative for Germany entered the Bundestag.’ The multicultural cant that binds political establishments together — for instance, using the word ‘refugee’ to describe an ambitious person intent on settling permanently in a European country — comes under scrutiny. What was an asset for the establishment turns into a liability, a sign of hypocrisy.

Salvini is good with language. He has managed to reframe humanitarianism as criminality. He colourfully describes the non-governmental organisations that transport migrants at sea as being bound up in the same ‘business’ as the mafiosi who guide them on land. A would-be African immigrant no longer needs to hire a boat that can get him to Europe — all he needs is a boat that can get him to the charitable rescue ship, funded by some billionaire, that you can see from the North African coast. ‘They won’t see Italy unless they see it on a postcard,’ he promises.

Salvini has relished confronting the billionaire George Soros, accusing him of using his charities ‘to fill Italy and Europe with migrants’. Attacking the Hungarian-born Soros is a rhetorical gambit that Orbán has long relished — but what appeared a fringe issue when it was confined to Hungary takes on a wider resonance when it enters the politics of one of the founding EU states. American complaints about the ‘meddling’ of other countries in the US election system invite scrutiny of the many billionaire-run foundations whose political activity abroad is subsidised (through tax deductibility) by the US government.

Salvini’s goal is to expose Macron as the kind of politician who favours wide-open immigration. No European leader can afford to be seen as a soft touch, though many seek a friendlier-looking way to carry out hardline policies. Danish prime minister Lars Løkke Rasmussen, for instance, lately suggested that Europe attack the ‘causes’ of migration.

That won’t work. The cause of the present wave of trans-Mediterranean migration is not poverty or anything that is within the power of the EU to correct. It is, ultimately, population growth. The population of Africa has almost tripled since 1980, and it is going to double again between now and 2050. While Europe’s population shrivels and shrinks over the next generation, the continent to its south is going to add — add, not have — 1.25 billion young people. Already there are millions of potential migrants stacked up in the dosshouses of Tripoli and Tunis and Istanbul and on the roads behind them, ready to converge on the first country that offers a hint of the welcome that European leaders gave in 2015.

How Europeans react to this population explosion will depend on whether they see it as bringing more helping hands or more mouths to feed. Salvini has found a set of nationalist arguments that win at the polls. But the institutions of the global economy remain powerful and persuasive, and Macron speaks for them in a fresher way than it is possible to do in the US or Britain or any country where the agenda of neoliberal deregulation has reigned since the 1980s. In eight months, the EU’s parliamentary elections will show us which of these two paths Europeans are inclined to take.

Salvini is good with language. He has managed to reframe humanitarianism as criminality

Spectator.co.uk/podcast Christopher Caldwell and Sophie Pedder on the future of European politics.