PARIS — A boat crowded with hundreds of Africans sailing across the Mediterranean after being turned away by Italy this week has exposed anew the shaky fault lines in Europe’s approach to the migrant crisis.
On Sunday, Italy’s new far-right interior minister, Matteo Salvini, ordered the Aquarius, a rescue ship operated by humanitarian groups, to stop 35 nautical miles off the coast of Italy, refusing to let it dock.
The ship is now on its way to Spain, which showed up its neighbors by solemnly announcing that it would “respect its international engagements” and accept the boat after Malta, too, refused it, and France stood idly by.
Brussels, the seat of the European Union, looked on in relative silence. There was no common policy to receive the Aquarius and no authority to impose one if there were.
The imbroglio was “symptomatic of the lack of coordination of a managed migration policy at the European Union level,” said Imogen Sudbery of the International Rescue Committee in Brussels.
The Italian refusal to offer safe harbor to a ship loaded with what aid groups described as 629 migrants — including 123 minors, 11 small children and seven pregnant women — was intended to underscore a long-simmering grievance.
The Italians have bridled for years that they have been left alone by their European Union partners on the front line on the Mediterranean with an unmanageable burden of migration that Mr. Salvini pledged to reverse in his recent election campaign.
But his refusal to accept the boat did more than pit humanitarian necessity against political expediency. It roiled tensions with European allies in ways that made President Trump’s performance at the G-7 summit last weekend look almost diplomatic by comparison.
By Tuesday, the Aquarius affair had erupted into full-blown sniping among allies, as four European governments traded mutual recriminations, reproaches and comeuppances.
President Emmanuel Macron of France accused Italy of “cynicism” and “irresponsibility” for refusing to receive the boat.
Coming from the French, the remarks amounted to a white-glove slap in the face. The Italians were having none of it.
The office of the Italian prime minister pushed back against “hypocritical lessons” from France, which has taken in a mere fraction of the tens of thousands of Africans arriving in Italy — some 120,000 arrived by sea in 2017 — and did not offer to take any of the latest.
France regularly forces migrants back across the Italian border, deports dozens of others and gives only grudging aid to the relative handful who make it through the first filter. This time, again, the French stood by, refusing to take in the Aquarius.
The Italians, disgusted with the French position, summoned France’s chargé d’affaires in Rome on Wednesday, an unusual diplomatic move between two usually friendly neighbors. Italy’s economy minister, Giovanni Tria, canceled a meeting with his French counterpart, Bruno Le Maire, in Paris.
Mr. Salvini appeared to be relishing the mayhem he was causing. “We reawakened Europe,” he told Corriere della Sera in an article on Wednesday.
“Ironically, one day we may discover that we were the ones to save Europe,” said Mr. Salvini, who has a history of euroskepticism and advocacy for leaving the euro.
On Wednesday morning, Mr. Salvini fleshed out his position in his first official address to Parliament, saying that Italy’s history of generosity did not deserve criticism from the French, who he hoped would offer their official apology as soon as possible.
Under a 2015 European Union migrant plan, France was to have accepted 19,174 migrants from Italy and Greece. In all it took only 4,677.
Mr. Macron tried to tamp down the flames on Wednesday, saying that France was “working hand in hand with Italy” to manage the migrant flow. But there was little sign of that, and less sign that he had mollified the Italians.
In Parliament, Mr. Salvini noted that from Jan. 1 to May 31, France had turned back 10,249 people, including women, children and the handicapped, at the border between the countries.
Mr. Salvini added that France had accepted only 640 out of the 9,816 migrants agreed upon in 2015 and said he looked forward to Mr. Macron’s accepting 9,000 migrants the next morning.
That seems unlikely. But the travails of the Aquarius have created the sharpest rifts yet in Mr. Macron’s governing party, with parliamentary deputies expressing anger at the government’s silence and inaction.
The French prime minister, Edouard Philippe, merely said that France would “help” the Spanish. Without saying it, France this week seemed to make its policy on migrants clear: rejection.
“The French government has missed an opportunity to distinguish itself in this affair,” said Sébastien Nadot, a parliamentary deputy in Mr. Macron’s Republic on the Move political movement. “Given the situation in France and Europe, I would have wished that for once we would be on the side of what is just.”
“Italy’s political situation is the result of the European Union’s egotistical approach to migration,” he added. “Italy is forcing us to face our responsibilities.”
Others tweeted their displeasure with the French government. “It should have been France’s duty to agree to accept the 600 men, women and children who are in danger,” said Saïd Ahamada, another deputy in Mr. Macron’s movement.
Corsica, a French region struggling for some measure of autonomy from Paris and always looking to mark differences with it, stepped in with an offer to help, but too late.
“We’ve got a vision of Europe and the Mediterranean, and we can’t accept that it’s only a zone of tension and fracture, and a cemetery,” said Gilles Simeoni, the head of Corsica’s executive council.
But how far that vision extends in Europe is precisely the issue.
Chancellor Angela Merkel of Germany insisted this week that it makes no sense for individual European countries to tackle illegal migration independent of one another, given the lack of borders within the core countries of the European Union.
She rejected her own interior minister’s tough migration plan, which would have allowed the police to reject migrants at the border if they were already registered in another European Union country.
“It is an issue that we must resolve at a European level,” Ms. Merkel said. “That is very important to me.”
Underscoring the imperative, Ms. Merkel spoke to reporters on Tuesday after meeting with Sebastian Kurz, the chancellor of Austria, who, like Mr. Salvini, was elected on a pledge to stop illegal migrants.
She and other leaders in the European establishment, including Mr. Macron and those in Brussels, know well that the longer the policy chaos goes on, the wider the opening for the far right and populist forces to exploit the migration issue.
In fact, Marine Le Pen, the leader of the far-right National Front in France, expressed support for the Italian stand. “Salvini’s reaction is salutary,” she said in a tweet. “They have got to go back where they came from.”
Adam Nossiter reported from Paris, and Jason Horowitz from Rome. Melissa Eddy contributed reporting from Berlin.