What rising tensions with Mexico mean for the US

Mexico is one of the United States’ most important partners and one of its most misunderstood.

The two countries share more than a border. They are bound together by trade, migration, supply chains, family ties, security concerns and a complicated political history. Now, that relationship is being tested by rising tensions over tariffs, the future of the U.S.-Mexico-Canada Agreement (USMCA), fentanyl, cartel violence, migration and Mexican sovereignty.

Pamela Starr, professor of the practice of political science and international relations at the USC Dornsife College of Letters, Arts and Sciences, has spent decades studying Mexican politics, Mexican foreign policy and U.S.-Mexico relations. Her new book, The Making of Mexico: Revolution, Reform, and Transformation, examines the historical experiences and “unwritten rules of behavior” that continue to shape how Mexico responds to today’s challenges.

In this Q&A, Starr explains what Americans often misunderstand about Mexico, how President Claudia Sheinbaum is navigating pressure from Washington, and why the future of U.S.-Mexico relations matters for American workers, consumers and national security.

When Americans think about Mexico today, problems at the border are likely top of mind. What do you wish more people understood about how deeply connected our two countries are?

Most Americans know about the headline issues of drugs and migration. Some know the U.S. runs a trade deficit with Mexico, and many imagine that this means the U.S. is exporting jobs to Mexico. But that is an incomplete view of a relationship that is very complicated and, on balance, highly beneficial to the United States.

For example, Mexico is our number one trading partner. It exports fruits and vegetables and minerals to the U.S., but it also exports autos and autoparts, medical devices, and computers. It imports more U.S. corn than any other country in the world, but also imports large quantities of pork, natural gas, gasoline and autoparts.

But we don’t merely trade with Mexico. We produce things together, trading inputs as we jointly produce stuff. For example, 74% of Mexican manufactured exports contain U.S. content. Further, it’s estimated that an “American” car crosses the U.S.-Mexico border eight times during its manufacture.

These deeply integrated supply chains reinforce our global competitiveness by keeping the cost of production lower than it would otherwise be. This helps the U.S. compete with China, generate investment, growth and job creation, and keep consumer prices down. And that’s just the economic relationship.

The Trump administration is pushing changes to the U.S.-Mexico-Canada Agreement, the trade deal that replaced NAFTA. Why should Americans who don’t follow trade policy care about what happens next?

Americans should care because changes to USMCA could affect their jobs, wages and the prices they pay for everyday goods. The agreement makes possible the cross-border production process that helps keep the U.S. economy internationally competitive and consumer prices low. Its rules governing trade and investment give companies the confidence to invest across borders while maintaining quality and controlling costs.

The U.S. does not appear to want to leave the agreement but rather to establish new rules designed to dramatically increase U.S. content in cars and other products and reduce Chinese inputs in North American supply chains. Companies may struggle to adapt, especially if the changes are substantial and must be implemented quickly. In the best case, they adapt. In the worst case, production is disrupted and costs rise, making U.S. companies less competitive with China and leading to job cuts, lower wages and higher consumer prices.

The decision to continue negotiating rather than renew USMCA under its current term has added to the uncertainty. Although the agreement remains in force, companies cannot be sure what future trade rules will look like. As a result, many are delaying investment in Mexico. And rather than shifting that investment to the U.S., as the Trump administration hopes, some may look to countries that may ultimately not be as reliable a partner.

Sheinbaum has had to respond to U.S. pressure on tariffs, migration and security while also defending Mexican sovereignty. How would you describe her strategy so far?

President Sheinbaum refers to her strategy for dealing with President Trump during the first year and a half of her presidency as “cool headedness.” She largely avoided responding in kind to Trump’s rhetorical provocations, built a working relationship through a series of phone calls that helped defuse potential conflicts, and responded to key U.S. demands for deeper cooperation on migration and security policy.

That strategy shifted, however, after the U.S. indicted several Mexican officials, including the sitting governor of Sinaloa, and demanded their arrest and extradition. For Sheinbaum, this crossed a line. She responded by invoking a long-standing Mexican strategy for dealing with excessive U.S. pressure: appealing to Mexican nationalism.

She argued that far-right forces in the U.S. were attempting to influence Mexican politics and use criminal indictments to shape who governs the country — the latest in a long history of foreign violations of Mexican sovereignty. Even so, she stopped short of accusing Trump directly, suggesting that she has modified, rather than abandoned, her strategy of “cool headedness.”

You have described U.S.-Mexico relations as shaped by an informal “autonomy within limits” accord, in which Mexico has had room to chart its own path as long as it did not cross certain U.S. red lines. Is that longstanding bargain beginning to break down?

The U.S.-Mexico relationship is in uncharted territory. For roughly a century, U.S. presidents largely followed two informal rules in dealing with Mexico: Disagreements were handled privately, and Mexico was given broad policy autonomy as long as it aligned with the United States when U.S. national security was at stake.

Historically, U.S. national security threats were understood as coming from foreign adversaries, such as the Axis powers during World War II or the Soviet Union during the Cold War. In the late 20th century, Washington increasingly pressed Mexico to cooperate on migration and drug trafficking, but those issues were not treated as national security threats that sharply constrained Mexican policy autonomy. Trump changed that.

The Trump administration expanded the range of U.S. red lines to include migration and drug trafficking, arguing that both threaten national security and require Mexico to meet U.S. demands. It has also raised the possibility of unilateral U.S. military action in Mexico and publicly pushed for joint military or police operations against cartels — both deeply sensitive issues for Mexico.

Mexico has rarely had to draw such explicit red lines with the U.S., and it cannot be sure how Washington will respond. For Mexico, the most important aspect of autonomy is limiting foreign influence in its domestic politics. That is why cooperation on issues such as containing the screwworm may be acceptable, while demands to arrest and extradite elected officials may not be.

Mexico has also approved a constitutional change allowing election results to be annulled if foreign interference is proven. Supporters say it protects Mexican sovereignty; critics warn it could be used to overturn unfavorable results. What could it mean for Mexican democracy and U.S.-Mexico relations?

This constitutional change is intended to curb support from internationally connected far-right groups for Mexico’s conservative opposition, which the Sheinbaum administration sees as a potential threat to its political survival and its ability to advance a leftist agenda. Citing alleged outside influence in recent right-wing electoral victories across Latin America, the administration argues that foreign — particularly U.S. — involvement in Mexican politics violates national sovereignty and that election results should be subject to challenge when such interference is proven.

Sheinbaum’s opponents, however, are concerned that the legislation is written so vaguely that it could be abused. Because it allows an election to be annulled if foreign interference is demonstrated, they fear government forces could invoke the provision broadly to overturn unfavorable results and preserve the governing party’s hold on power. The resulting uncertainty about whether future elections will be free and fair is significant.

Your new book explores the “unwritten rules of behavior” that shape Mexico’s politics, economy and foreign policy. Which of these rules are most important for Americans to understand?

“Autonomy within limits” is the most important unwritten rule shaping Mexican foreign policy. But Mexico’s domestic development has also been shaped by a historically rooted tolerance for corruption, the bending of laws and government favoritism in the economy. These patterns have hindered its fight against organized crime and its efforts to build a more dynamic national economy. Because the U.S. has had a different historical experience, some Americans have limited sympathy for the resulting policy challenges and see Mexico primarily as a source of problems rather than opportunity.

These unwritten rules are certainly not unique to Mexico; every country’s behavior is shaped by its history. Government in the U.S. was once deeply corrupt, for example, but the country largely succeeded in changing that accepted pattern of behavior, despite some recent backsliding. In Mexico, the powerful influence of the Catholic Church in politics and the economy was accepted as normal for centuries before being sharply curtailed in the early 20th century.

History is not destiny, but unwritten rules can be formidable obstacles to change because they define what societies consider normal and can be especially difficult for outsiders to recognize or understand.