German Chancellor Angela Merkel knows that there is nothing to gain in isolating US President Donald Trump even further than he has chosen to do himself. And, with the G20 summit in Germany coming up at the beginning of July, time is running out to unite the world's 20 leading economies around some kind of bottom-line idea on a way forward. Merkel's hope is that, even if the summit doesn't quite create unity, the G20 can arrive at least "a certain amount of stability." Failure - as exemplified by the US's public rift with its G7 allies over climate change - is not an option, which doesn't mean it can't happen.

Merkel needs allies who are willing to put their money where their mouths are on the issues that she cares greatly about. One is getting a G20 financial commitment to address the conditions that lead so many people in Africa to emigrate. She knew that she could find such partners on her trip to Latin America, where she carefully tried to avoid the appearance of forging an anti-Trump alliance. Germany may not depend on the United States for trade as much as Mexico does - 80 percent of its exports go north of the border - but officials in Berlin know that the country is almost literally defenseless without the United States, both militarily and when it comes to counterterrorism intelligence.

The chancellor was welcomed as a breath of fresh air in Latin America, especially in Mexico, where the constant barrage of threats and humiliation coming out of Washington has created visible pain. President Enrique Pena Nieto attempted to put a positive spin on the looming renegotiation of the North American Free Trade Agreement, as demanded by the United States. He called it "a great opportunity," which came across like whistling in the dark. Merkel, in contrast, brought to Mexico the promise of deeper trade ties - along with a business delegation to back up her words. Several times she stressed that "building a wall" would not end migration and that no country or leader alone could tackle the world's challenges. Does that sound like the "leader of the free world" to you? It certainly did to those who greeted her. Introductions ranged from "important leader" to "the most important politician in the world."

Merkel was soft-spoken but firm in her commitment to free markets. There was no grandstanding on principles. There was no need for that: In its own way, global business continues usual - even on the US-Mexico border, which automotive components continue to cross several times before a completed car leaves the assembly line. And US governors know very well that many of the jobs in their states come courtesy of German companies. Below the level of the White House, there is also an acute understanding that when the United States leaves a market, other countries, often China, will move in. That is a market reality that leaves no room for rhetoric.

When a Mexican student asked Merkel about her time studying physics, the chancellor retold the story of how she used to spend so long thinking about how to approach scientific challenges that her classmates had already taken the parts that she would need for her experiment. The boys were faster but often failed because they hadn't thought things through. As chancellor, Merkel is once again finding herself picking up the pieces left behind by a "what happens if I press that button?" type of guy - who happens to be the president of the United States. But, just as Merkel's fellow students were unable to change the laws of physics, Donald Trump won't change the ways in which the world migrates, the climate changes or nations do business. The big question is: Who is going to tell him that? More importantly: Will he listen?

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