Mexico’s new president, Andrés Manuel López Obrador (AMLO), looks like the perfect adversary for Donald Trump. The American represents the financial elites and inequality AMLO has railed against his entire career whereas he himself embodies the hopes of Mexico’s poorest, many of whom have sought a better life in the United States — and who have been disparaged by Trump as criminals and rapists.

But the two leaders also share traits: a populist style, policy light on detail and nostalgia for a bygone era.

The two have avoided a confrontation on trade. Immigration and security provide more opportunities for compromise — but could just as easily cause the relationship to come unstuck.

Trade

AMLO and Trump have managed to side-step contentious trade talks. With Mexico the United States’ second largest export market and about 80 percent of Mexican exports going the other way, there was plenty at stake when Trump pressed for a renegotiation of NAFTA last year.

But AMLO’s predecessor, Enrique Peña Nieto, was able to complete what is now known as the USMCA trade deal a day before AMLO’s inauguration and in so doing avoided a potential standoff.

Immigration

The border between Mexico and the United States is the busiest in the world, but immigration levels are lower than they have been in years. In 2000, of the 1.6 million illegal migrants apprehended, 90 percent were Mexican. Last year, out of 311,000, fewer than half were Mexican. In fact, there are more Mexicans returning home than illegal immigrants coming the other way. So what is the problem?

According to the BBC, asylum applications have jumped significantly: from 4,995 in 2005 to 99,035 in 2018. In the border city of Tijuana there are currently some 6,000 asylum seekers, principally from Central America, awaiting entry into the United States. Further caravans of migrants are on their way.

Trump campaigned on a hardline approach and has increased the military presence at the border. His policy of “metering”, or limiting the number of asylum applications that can be processed on a given day, has created a huge backlog. Asylum seekers are stuck at the border and forced to wait for weeks or months — or even longer.

AMLO has called on his American counterpart to provide financial aid to the so-called Northern Triangle of Honduras, El Salvador and Guatemala, where the majority of these asylum seekers come from. $30 billion has been muted as a contribution from the USMCA.

The crisis in Tijuana gives the two presidents an opportunity to rebuild trust through cross-border cooperation, but that would require a dynamic shift in momentum. It was only in April that the Mexican Senate responded to Trump’s separation of migrant children from their families by calling for an end to migration and security cooperation altogether.

Immigration policy offers few quick fixes. Should either leader find their popular support dwindling, they may prefer to play to their base and make full use of anti-Trump or anti-migrant sentiment. A border closure, as Trump has threatened, could quickly cost both parties billions of dollars in lost trade and result in cartels switching from trafficking in drugs to smuggling people.

Drugs

Although Mexico and the United States have worked closely to tackle the flow of illegal drugs to the north, and of money and guns to the south, a divergence in policy could result in populist collision rather than pragmatic compromise.

AMLO has promised an alternative to the failed drug policies of his predecessors. He has spoken of regulating opium for medical use, decriminalizing marijuana and giving amnesty to minor drug offenders. This would mark a shift away from the militarized war on drugs that has claimed an estimated 200,000 lives since 2006.

Most of Mexico’s drug production, and the violence it creates, is due to American demand and the fragmentation of the criminal landscape resulting from the targeting of drug kingpins.

But Trump still believes in a “tough on drugs” approach and, at home, has cracked down on medical marijuana prescriptions, aiming for a reduction of one-third within three years. The drug kingpin strategy is likely to continue with his support.

Unpredictability

There is something improvisational about both leaders. They have stated goals but no obvious plans for how to achieve them.

Last month, AMLO abruptly declared that he would cement a formal military role in Mexico’s domestic security operations after months of espousing demilitarization.

It is this kind of unpredictability, displayed by both men, which means that, however tightly bound American-Mexican interests may be, it could take as little as a drop in the polls for their rhetoric to be ratcheted up and relations to be damaged.