Boil this down to its essence, and Trumpism states: When you lose, I win. Being strong equals being right. And if you want to advance your own interests, it is legitimate to inflict damage on others.

This is not a path that Germany can follow, and it is not a path that Germany can let its European neighbors follow, either. If Trumpism had been applied to Germany in 1945, my country would have become a province of the Soviet Union, and Western Germans would never have bought a pair of Levi’s or a bottle of Coke, let alone the idea of America as a beacon of freedom. If Mr. Trump was right and internationalism led to economic disaster, Germany should have one of the highest unemployment rates in the world. In fact, it has one of the lowest.

Does the European Union, arguably the best example of multilateral governance in the world, have flaws? Has it created too much red tape? Does it fail to fulfill central promises? You bet. But Mr. Trump’s idea that “bureaucracy” as such impedes sovereignty is just as narrow-minded as the idea that Britain will be better off outside the European Union. Brussels’ bureaucracy, first and foremost, has enormously facilitated trade within Europe. The British are about to experience what happens without it.

Ms. Merkel knows these things, believes them in her bones. And she seems to know that, in 2017, it is up to her to defend them. It was probably no coincidence that she announced she would run for a fourth term only after the Brexit vote and after Donald Trump had moved to the White House.

What will it mean for Ms. Merkel to pick up the standard of the free world? Expect her to defend and promote the European Union as a bulwark of liberal internationalism, against an America that might well begin to attack it. At the same time, expect her to do more to mitigate the negative consequences of political and economic internationalism on everyday Germans and Europeans. In Ms. Merkel’s view, this buffering has not happened in the United States, because of the lack of a “reasonable social system,” as she put it in an interview.

Merkelism, in short, draws a very different conclusion from Trumpism about globalization’s unsettling effects. Mr. Trump wants to disrupt and destroy, Ms. Merkel seeks to continue but correct. If the free world is best led by success, with step-by-step repair preferable to scrapping, then the German chancellor seems to be the right woman, at the right moment, for the job.