PARIS — The German government of Chancellor Angela Merkel falls, torn apart by demands from her conservative interior minister, Horst Seehofer, that refugees already registered in another European Union state be thrown out of Germany.

The xenophobic Alternative for Germany, or AfD, enters a new nationalist governing coalition. The party’s cry of “take back our country and our Volk!” echoes through Berlin.

Congratulatory calls pour in from the nationalist leaders of Hungary, the Czech Republic, Poland, Italy, Austria — and the United States. The American ambassador to Germany tweets his approval.

European Union leaders, buckling before the anti-immigrant tide, opt for the establishment of large detention centers for all migrants. Asylum seekers whose claims are verified will be admitted, while economic migrants merely in search of a better future will be evicted.

Riots erupt in these vast walled compounds. Rapid triage proves impossible. Conditions fester. Matteo Salvini, the rightist Italian interior minister, declares that a disastrous mistake has been made. The detention centers should have been located in North Africa. He defends his orders to the Italian Coast Guard to ignore calls for help from ships filled with migrants who, he says, may prove to be criminals and rapists.

The abduction of a Russian girl by Moroccan migrants at a Spanish beach resort causes an uproar. It turns out to be “fake news,” the work of Russian cyber-geeks deployed for information warfare, but not before rightist leaders across the European Union have denounced the “foreign animals” holding “little Tatiana.” Spain’s fragile government collapses.

Germany, Italy, the Czech Republic and Hungary announce that they are leaving the Schengen area and will reintroduce border and passport controls. The free movement of people, a cornerstone of the European Union, collapses. President Trump congratulates Europe on “coming to its senses at last.” His ambassador to Germany tweets a hymn to “rediscovered, strong nations.”

President Trump, arriving in Brussels for a NATO summit, explodes at the sight of the vast new $1.3 billion NATO headquarters building — “a scandal, a monstrosity, an insult to ordinary Americans.”

He declares that NATO is no longer an alliance; it’s a cost center. The United States is paying too much. Why, he asks, are European armies not being used to round up “the immigrants who infest your countries and destroy your Christian cultures”?

Turning on his former friend President Emmanuel Macron he denounces the French defense of a united Europe as “weak, weak.” Asked about the Trump-Macron relationship, a spokesman for Macron responds, “As we say in France, ‘les grands amours finissent toujours mal’— great loves always end badly.”

The NATO summit proves more fractious than the recent G-7 summit in Canada. Trump rages and sulks. He pouts and pesters. He declares that just as he has stopped joint United States military exercises with South Korea because they are a provocation to “my friend Kim Jong-un,” so he has decided, after consultation with “my friend Vladimir Putin” to withdraw from NATO military exercises in Poland and the Baltics because such exercises are a “provocation to Russia.”

A briefing paper prepared by his national security adviser, John Bolton, is leaked. It defines the president’s strategic objective as “the destruction of the World Trade Organization, NATO and the European Union.” Much progress, it notes, has been made toward all three goals. “The liberal democratic club is crumbling under the weight of its own decadence and political correctness.”

President Putin, citing “crimes” against the Russian minority in Estonia, sends the Russian army into Estonia, a NATO member. He insists that there has been no “invasion” but that ethnic Russians in Estonia have justifiably taken up arms.

Satellite imagery of Russian troops crossing the border is dismissed by Trump as “fake news.” Leading Republicans unanimously support his position.

NATO fails to invoke Article 5, which says an attack against any one NATO member must be considered an attack against them all. Allied governments abandon Estonia to its fate.

NATO disbands. Putin proposes replacing it with the Alliance of Authoritarian and Reactionary States, or AARS. Trump says he finds the idea “interesting.”

Britain leaves the carcass of the European Union. Germany, under its rightist coalition, announces it is giving up the euro and readopting the deutsche mark. The eurozone collapses. The American ambassador to Germany tweets his delight.

The European Union disbands. Its flag is lowered at the French-German border, where work on a high-tech wall flanked by banks of barbed wire has begun. Trump and Marine Le Pen, the French National Front leader, tweet their approval. Germany announces a strategic alliance with Russia. The United States Supreme Court rules, on “national security” grounds, that due process is not required before expelling undocumented immigrants. Mass deportations begin. Trump tweets that due process “is overrated.”

It could not happen. Of course, it could not happen. Only a fool would believe for a moment that it could.