Whatever her accomplishments as pathbreaking female politician and respected leader of Europe’s dominant economic power, Angela Merkel will go down in history for her outburst of naivete over the issue of migration into Europe during the summer of 2015.

Her announcement on Monday that she will vacate the leadership of Germany’s ruling center-right Christian Democrats marks the culmination of what has been a slow denouement of Merkelism.

She had seen the vote share of her long dominant party shrink in one regional election after another. The rebuke given to her last weekend in Hesse, containing the Frankfurt region with its booming economy, where she had campaigned extensively, was the final straw. Her CDU’s vote had declined 10 points since the previous election, their voters moving toward the further right (Alternative fur Deutschland or AfD). Meanwhile, the further left Greens have made dramatic gains at the expense of Merkel’s Social Democrat coalition partners.

Long the emblematic figure of “Europe,” hailed by the neoliberal Economist as the continent’s moral voice, long the dominant decider of its collective foreign and economic policies, Merkel will leave office with border fences being erected and disdain for European political institutions at their highest pitch ever. In this sense, she failed as dramatically as her most famous predecessors, Konrad Adenauer, Willy Brandt, Helmut Schmidt, and Helmut Kohl, succeeded in their efforts to make Germany both important and normal in the postwar world.

One can acknowledge that while Merkel never admitted error for her multiculti summer fling (beyond wishing she had communicated her goals better), she did manage to adjust her policies. By 2016, Germany under her watch was paying a healthy ransom to Turkey to keep would-be migrants in camps and preventing them from sailing to Greece. Merkel’s departure will make the battle to succeed her one of the most watched political contests in Europe. She has turned migration into a central and quite divisive issue within the CDU and Germany, and the party may decide that it has no choice but to accommodate, in one way or another, the voters who have left them for the AfD.

Related to the issue of who should reside in Europe (objectively the current answer remains anyone who can get there) is the question of how are such questions decided. In July 2015, five years after asserting in a speech that multiculturalism has “utterly failed” in Germany (without addressing what policies should be pursued in an increasingly ethnically diverse society) and several weeks after reducing a young Arab girl to tears at a televised forum by telling her that those whose asylum claims were rejected would “have to go back” and that “politics is hard,” Merkel changed course.

For those interested in psychological studies of leadership and decision making, it would be hard to imagine a richer subject. Merkel’s government first announced it would no longer enforce the rule (the Dublin agreement) that required asylum claimants to be processed in the first country they passed through. Then she doubled down. The migrants fleeing the Syrian civil war, along with those who pretended to be Syrian, and then basically just anyone, could come to Germany.

“We can do this!” she famously declared. Europe, she said, must “show flexibility” over refugees. Then, a few days later, she said there was “no limit” to the number of migrants Germany could accept. At first, the burgeoning flood of mostly young male asylum claimants produced an orgy of self-congratulatory good feeling, celebrity posturing of welcome, Merkel greeting migrants at the train station, Merkel taking selfies with migrants, Merkel touted in The Economist as “Merkel the Bold.”

Her words traveled far beyond those fleeing Syria. Within 48 hours of the “no limit” remark, The New York Times reported a sudden stirring of migrants from Nigeria. Naturally Merkel boasted in a quiet way about how her decision had revealed that Germany had put its Nazi past behind it. “The world sees Germany as a land of hope and chances,” she said. “That wasn’t always the case.” In making this decision personally, Merkel was making it for all of Europe. It was one of the ironies of a European arrangement whose institutions were developed in part to transcend nationalism and constrain future German power that 70 years after the end of the war, the privately arrived-at decision of a German chancellor could instantly transform societies all over Europe.

The euphoria, of course, did not last. Several of the Merkel migrants carried out terror attacks in France that fall. (France’s socialist prime minister Manuel Valls remarked pointedly after meeting with Merkel, “It was not us who said, ‘Come!’”) Reports of sexual assaults and murders by migrants proved impossible to suppress, though Merkel did ask Mark Zuckerberg to squelch European criticism of her migration policies on Facebook. Intelligent as she undoubtedly is (she was a research chemist before entering politics), she seemed to lack any intellectual foundation to comprehend why the integration of hundreds of thousands of people from the Muslim world might prove difficult.

Merkel reportedly telephoned Benjamin Netanyahu to ask how Israel had been so successful in integrating so many immigrants during its brief history. There is no record of what Netanyahu thought of the wisdom of the woman posing this question.

In any case, within a year, the Merkel initiative was acknowledged as a failure by most everyone except the chancellor herself. Her public approval rating plunged from 75 percent in April 2015 to 47 percent the following summer. The first electoral rebuke came in September 2016, when the brand new anti-immigration party, the Alternative fur Deutschland, beat Merkel’s CDU in Pomerania.

In every election since, Merkel’s party has lost further ground. Challenges to her authority from within her own party have become more pointed and powerful. But the mass migration accelerated by her decision continues, albeit at a slightly lower pace.

Angela Merkel altered not only Germany but the entire European continent, in irreversible ways, for decades to come.

Scott McConnell is a founding editor of The American Conservative and the author of Ex-Neocon: Dispatches From the Post-9/11 Ideological Wars.