MEXICO CITY - There can be many readings of the letter recently sent by Mexico's President Andrés Manuel López Obrador (aka AMLO) to U.S. President Donald J. Trump. But one thing is sure: it is a document prompted by and serving political priorities at home. In that sense, it was at least a great success. In addition to massive popular support since López Obrador began his presidency in December, he can now boast that he enjoys the sympathy — if not recognition of social sectors like businesspeople, commentators or critics who were not with him before. It is a notable achievement. One commentator captured the new mood: "Trump has managed to convert AMLO from a leader into the head of state." The question remains though: does this support solve his main problem.

Context is fundamental. The main characteristic of the 10 months since AMLO began to run the country has been constant confrontation in an already polarized country. The president's attack strategy has worked so far, but only because the financial markets, unlike other periods in our recent history, were indifferent to domestic debates.

While exports flow, the interest rate spread is maintained and rating agencies ignore their own admonitions on two vast projects, the Dos Bocas refinery and Maya railway, investors will see no reason to change strategy that has proved highly profitable.

In One Hundred Years of Solitude, Colombian novelist Gabriel García Márquez creates characters who live in parallel worlds that are visible, but not accessible. His world of magic realism doesn't seem too distant from the events of recent days. Trump — a character from a bewitched and less magical reality — duly combined two of his obsessions to conjure a Mexican nightmare. His loathing of trade deficits as bad for the economy is well-known but this time he merged with illegal immigration, perhaps the overriding theme of his 2016 election campaign and perfect launchpad for his reelection bid. To each side its own magical realism...

Decisions by the Mexican government barely provoke a murmur among Americans.

Whatever happens in the long term with tariffs and elections, the impact on Mexico could be extraordinary. The real asymmetry in the neighbors' relations is not in their governments' respective powers but in the disproportionate impact any measure taken across the border has on Mexico. A decision by the Mexican government barely provokes a murmur among Americans, but just the threat of tariffs pushed the peso down 3%. This follows a historical pattern and has also marked Trump's conduct since his 2016 campaign.

The problem with his recent tactic is that he strikes at our country's stability, and there is little the Mexican government do to change the reality of migration in the short term. At the same time we all know in Mexico that the government has been promising for decades to stem migration, but have not done anything. As this never had consequences the idea here was that it was never a "real" issue, though Trump's arrival has changed that.

Now is the time to redirect domestic policies. AMLO has managed to achieve a political truce, so far largely thanks to Trump, and inadvertently confirmed the adage that the best domestic policy is a good foreign policy.

The opportunity is in his hands: Mexico's new president is very much in charge and can either choose to persist in his divisive strategy, or to try to include the entire population in his vision and become the transformative leader this country so desperately needs. It is actually a unique opportunity, and we might even avoid the worst consequences of the actions until now of both these unlikely presidents.

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