Democratic Congress majority and Mexico-U.S. relations after Trump’s midterm losses, Digi Mart USA News: Many optimists believe a Democratic victory could benefit Mexico, but that benefit will depend largely on the ability of Claudia Sheinbaum and her team to negotiate with a Washington divided between the presidency and Congress, which may hold opposing and even conflicting positions.
Donald Trump lost political control of both chambers of the U.S. Congress on November 3, as Democrats regained them in midterm elections that punished the Republican Party even in states where defeat seemed unlikely.
The result alters the second half of his term, though it is far from turning the president into a figure without power.
The new majority can block legislative initiatives, investigate administration officials, demand documents and testimony, condition budget allocations and, from the Senate, reject presidential appointments. The change will take effect with the Congress that takes office on January 3, 2027, but in the meantime Trump keeps the presidency, control of federal agencies and the executive powers he has used to impose his trade, immigration and security agenda, along with his veto, which would require two-thirds of both chambers to override.
Mexico has reasons to find favorable possibilities in the result, though it would be a mistake to celebrate the Republican defeat as if it were a diplomatic victory for Claudia Sheinbaum, because a president weakened at the polls can still take decisions that are very costly for his neighbor. The uncertainty lies in whether he will seek agreements to recover authority or conflicts that display the authority he still retains.
In his regular column for El Universal this Wednesday, former foreign minister Jorge G. Castañeda examines three forecasts about Mexico that, in his view, rest on mistaken interpretations of U.S.
politics, beginning with the assumption that Trump would need a spectacular blow against Mexico to recover votes before November 3. Versions circulated about possible military operations on Mexican territory and actions against high-profile political figures, but none of that occurred before the elections, which requires recalling that a possible threat is not an inevitable event.
Castañeda argues that Mexico held a secondary place in the calculations of the U.S. electorate, a reasonable observation that requires clarification: migration, drugs and the border did appear in the political debate, though there is not sufficient evidence to suppose that an operation against a Mexican politician by itself would have altered the election result.
The former foreign minister accuses the government of deliberately fueling those versions, an intention that is not demonstrated by the simple failure of the forecasts.
The first issue is the USMCA, whose extension on its current terms Washington rejected on July 1, 2026, during the joint review with Mexico and Canada. That decision did not cancel the agreement, which remains in force and must undergo annual reviews starting in 2027 while the three countries do not agree to extend it.
Absent renewal or early withdrawal, its expiration is scheduled for 2036.
The difference is decisive: a treaty in force allows trade operations to continue under its provisions, while an unresolved review creates lasting doubt about future rules, which can weigh as much as a tariff on investment and production decisions of an automaker, an electronic components supplier or an agricultural producer.
During 2025 Mexico was the leading trading partner of the United States in goods and services combined, according to the Congressional Research Service of that country, in a relationship whose supply chains are so intertwined that a part made in Mexico may incorporate U.S. inputs, cross the border several times and end up in a vehicle sold in either market.
Damaging that integration therefore also harms U.S. economic interests.
On October 28, just six days before the election, Sheinbaum reported that Economy Secretary Marcelo Ebrard was still talking with U.S. Trade Representative Jamieson Greer and Commerce Secretary Howard Lutnick.
She acknowledged progress and admitted pending disagreements, including Mexico’s push for a significant reduction in tariffs on the automotive sector, steel and aluminum under Section 232 of U.S. law.
Castañeda’s second objection concerns a trade agreement that some expected before the vote and that also did not arrive. The complexity of negotiations, the available timelines and Washington’s priorities made it unlikely to resolve sectoral tariffs, regulatory differences and the continuity of the treaty all at once.
There is a difference, however, between an unfulfilled promise and a negotiation that was not concluded. On October 28 Sheinbaum explicitly spoke of checking whether an agreement was feasible before the elections, without announcing that one had been signed or guaranteeing its conclusion.
What was objectionable was turning a possibility into an almost certain expectation, especially when uncertainty affects real investment and employment decisions.
These duties should be distinguished from the general taxes Trump attempted to justify under the International Emergency Economic Powers Act. On February 20, 2026, the U.S.
Supreme Court ruled that the law did not grant the president authority to impose tariffs. That ruling limited his trade tools without closing the discussion over other instruments, including Section 232 sectoral tariffs.
The Democratic Congress will be able to demand information on the USMCA negotiations, discuss their economic effects and exercise its legislative authority when a treaty modification requires changes to U.S. laws.
It would be incorrect, however, to say that any adjustment will automatically receive its approval, because the review, some trade understandings and measures that can be carried out with existing powers will still depend largely on the White House.
Nor should Democrats be credited with an unconditional disposition to favor Mexico. Their relationship with unions and environmental advocates can translate into stricter demands on wages, collective bargaining, rules of origin, energy and competitive conditions, as shown by the continued validity of the USMCA rapid response mechanism, which has already been used as a pressure tool.
On November 2, one day before the elections, the U.S. trade office activated a new review over alleged labor rights violations at the Mexican company Madobox.
The possible benefit for Mexico lies in broadening negotiation beyond presidential will and finding support among U.S. lawmakers, business leaders and workers interested in preserving productive integration.
There is also the risk of facing a more demanding and prolonged review, since Congress may oppose Trump’s arbitrary protectionism while also demanding new obligations from Mexico.
The bilateral dispute is not limited to the treaty. Washington seeks greater control over Chinese inputs entering North American industrial chains, questions Mexican energy decisions and has used tariff threats to press for water deliveries from the Rio Grande under the 1944 treaty.
Trade, security and border commitments may therefore end up mixed in a single political negotiation, even though their legal foundations differ.
The elections produced another especially important result for Mexico. Democrat Gina Hinojosa defeated Republican Governor Greg Abbott in Texas, and Democrat James Talarico won the U.S.
Senate seat against Ken Paxton. The loss of those positions in one of the largest Republican strongholds changes the political landscape of the state that shares with Mexico a border of extraordinary commercial and migratory activity.
Abbott had made border security one of his government’s main banners through Operation Lone Star, launched in 2021, which involved deployments of the Texas National Guard, state agents, barriers and other containment measures. Hinojosa may review the priorities, spending and procedures that depend on the state government, with the possibility of easing conflicts and fostering a more constructive relationship with Mexican authorities.
But Texas does not decide federal immigration policy, so the new governor will lack authority to cancel ICE operations, change U.S. entry requirements on her own or block a federal deportation order.
It will also be necessary to observe the balance of power in the state legislature and Hinojosa’s effective capacity to modify inherited decisions.
The human cost of Trump’s immigration policy can already be measured with data. The Migration Policy Institute estimated about 980,000 deportations and returns of people of various nationalities during the first eighteen months of his second term, between January 2025 and July 2026.
According to that research, roughly one-fifth of those in the total had criminal conviction records, a proportion that requires distinguishing between border control, formal removals and detentions carried out within the United States.
A Democratic majority will have greater opportunities to investigate raids, conditions in detention centers, contracts and the budgets of immigration agencies, and to demand procedural guarantees and combat documented abuses. None of those powers means deportations will cease in January, since Trump will continue directing federal law enforcement and Democrats have not proposed giving up border control.
For Mexico, the difference will be measured in divided families, receiving communities, pressure on border cities and, eventually, the incomes of households that depend on remittances. A reduction in indiscriminate operations would be favorable, though promising it now, before knowing the decisions of the new Congress and the presidential response, would be risky.
The Mexican government carries an additional responsibility, since its territory receives deported Mexican nationals and people of other nationalities expelled or transferred by the United States. That situation requires reception and assistance policies and coordination with local governments, because any improvement in the treatment of migrants will also depend on what Mexico does with those who arrive in its own cities.
Security is the most delicate terrain. According to a Congressional Research Service report updated in September 2026, the United States has designated eight criminal groups based in Mexico as foreign terrorist organizations, including the Sinaloa Cartel and the Jalisco New Generation Cartel.
That designation expands the possibilities for imposing financial sanctions, immigration restrictions and criminal charges for certain forms of material support to those organizations.
It is essential to clarify that this designation applies to criminal organizations, not to the Mexican state, and that by itself it does not authorize a U.S. military incursion into Mexican territory.
That legal distinction gains particular importance in light of Trump’s threats to use force against drug traffickers operating in Mexico.
Congress may investigate military operations, question their legal foundations, review authorizations and discuss the use of public resources. A Democratic majority could therefore raise the political cost of any unilateral intervention, though its ability to impose definitive restrictions would run into the presidential veto and disputes over the powers of the commander in chief.
No U.S. parliamentary majority will absolve the Mexican government of its obligation to combat drug trafficking, because synthetic drug production, corruption that protects criminal businesses and money laundering networks will remain on the bilateral agenda.
It would be absurd to expect Democrats to adopt an indulgent attitude toward cartels simply because they disagree with Trump.
Mexico, in turn, must insist on U.S. responsibility.
Arms trafficking into Mexican territory, the financial operations of criminal organizations and demand for drugs north of the border are part of a shared problem that requires cooperation with verifiable results and respect for sovereignty, without turning every difference into a pretext for military threats.
The plan the White House prepared before losing
An investigation that calls for greater caution over the coming months was published on November 1, two days before the vote, when Reuters reported that the White House had spent months preparing a strategy to govern without congressional support. That information was obtained from an administration official and two people familiar with the preparations who spoke on condition of anonymity.
According to that report, since April Stephen Miller, deputy chief of staff and a leading driver of immigration policy, Russell Vought, director of the Office of Management and Budget, and White House lawyers participated in the planning. The legal team, led by Will Scharf, examined the scope of presidential powers and how to defend them in court.
According to the report, the matters under review included new tariff decisions, visa restrictions, immigration provisions and changes in the management of federal resources that could be implemented without new legislative authorization. Responses to congressional investigations and document requests were also being prepared.
Reuters described plans still under study, not measures that should be considered approved or executed.
That detail changes the meaning of the Republican defeat. The administration did not wait for the electoral results to consider how it would retain political initiative.
For months it had been seeking the legal and administrative margins that would allow it to keep acting in the face of an unfavorable Congress. Trump himself had anticipated that he would resort to his veto and could later negotiate agreements with Democrats.
Specialists at Brookings and Chatham House, two of the best-known and most influential political research and analysis centers in the world, known as think tanks, had warned that an opposition Congress would not eliminate executive powers in foreign policy, trade and security. Their analyses raised the possibility of a presidency more inclined toward unilateral decisions and litigation.
Those warnings remain prospective and do not prove that the White House has already decided to take a specific action against Mexico.
Castañeda’s third warning is especially pertinent. U.S.
presidents who reach the final stretch of their terms, unable to seek reelection and facing an unfavorable Congress, often find in foreign policy a field where they can still make major decisions. He cited the international initiatives of Richard Nixon, Ronald Reagan, Bill Clinton and Barack Obama, which he recalled in circumstances of internal wear or limitation that differed from the present.
These precedents do not constitute a historical law, nor do they allow anticipating that Trump will choose a conflict with Mexico. They do, however, dismantle the unjustified confidence that a legislative defeat will force him to focus exclusively on domestic problems.
Here the contradiction that should concern us appears. Trump may lose the capacity to pass laws while retaining sufficient instruments to trigger a tariff crisis, order immigration operations or heighten tensions over cartels.
A electoral defeat could therefore push him toward negotiation or, on the contrary, encourage him to demonstrate that he still exercises presidential authority on matters that remain under his control.
Claudia Sheinbaum must negotiate with a Republican White House and a Capitol led by Democrats. Their interests may coincide in protecting U.S.
industries and demanding results against drug trafficking, but differ in how immigration law is applied, the scope of tariffs and military intervention outside U.S. territory.
The Mexican strategy must be broader than the personal relationship between the two presidents. It will be essential to cultivate agreements with lawmakers from both parties, state governments, unions and companies that depend on North American production chains, taking advantage of the openings the Democratic victory creates without turning outreach to Congress into a political challenge against Trump.
At the same time, the Mexican government will need to prepare legal and trade responses to new tariff measures, strengthen verifiable security cooperation and anticipate the effects of possible changes in deportations. These tasks cannot wait until the new Congress takes office, because the investment and negotiation calendar does not stop while Washington resolves its internal disputes.
In reality, Democrats do not represent a guarantee of concessions to Mexico. They may defend the USMCA against Trump’s uncertainty and prove stricter on labor conditions, environmental commitments and Mexican energy policy, just as they may challenge a unilateral military intervention while demanding deeper investigations into the protection networks of drug trafficking.
It should not be forgotten that an uncomfortable possibility remains: a Trump defeated at the polls, concerned with defending his government and determined to show he still commands may prove for some time more unpredictable than a president strengthened by a majority of his own. That is reason enough for Mexico to prepare both for its agreements and for its threats, without taking either path for granted.
The content of this column is the sole responsibility of the columnist.
