Why it Matters
A new Congressional Research Service (CRS) report on U.S.-Mexico trade relations arrives at a pivotal moment: the Trump administration's primary tariff tool against Mexico has been struck down by the Supreme Court, a replacement authority is ticking toward expiration, and a mandatory review of the foundational North American trade agreement is underway. The decisions made in the coming months will shape the most valuable bilateral trading relationship in the world.
The Big Picture
Mexico is the United States' top trading partner. According to the CRS report, the two countries recorded $976.1 billion in total goods and services trade in 2025, making it the largest bilateral goods trading relationship in the world.
That relationship is now operating under significant legal and political stress.
The administration had originally imposed tariffs on Mexico in March 2025 under the International Emergency Economic Powers Act (IEEPA), citing a declared national emergency over fentanyl trafficking and immigration. But in February 2026, the Supreme Court ruled that IEEPA cannot be used to impose tariffs, invalidating that authority entirely.
The administration pivoted to Section 122 of the Trade Act of 1974, imposing a 10 percent tariff on U.S. imports from Mexico effective February 24, 2026. The catch: Section 122 is a time-limited authority, capped at 150 days. That clock is running.
There is one significant carve-out. Goods that qualify under the United States-Mexico-Canada Agreement (USMCA) rules of origin are exempt from the 10 percent tariff, preserving preferential treatment for USMCA-compliant trade. That exemption creates a two-track system, rewarding supply chains built around North American content rules while penalizing those that don't qualify.
Complicating everything further, the USMCA itself is subject to a mandatory 2026 Joint Review, at which the United States, Mexico, and Canada must decide whether to extend the agreement. The review is happening in the middle of an active tariff dispute with one of the two other parties.
Political Stakes
For the administration: The Supreme Court's ruling is a direct constraint on executive trade power. With IEEPA off the table, the administration's ability to use tariffs as geopolitical leverage against Mexico, particularly on immigration and fentanyl, is now legally narrower. Section 122 fills the gap for now, but its 150-day ceiling means the administration will need to either negotiate a resolution, seek new legal authority, or watch the tariffs expire. None of those options is without political cost.
For Congress: The CRS report notes that members are actively considering how to engage in USMCA consultations, what priorities to assert, and what objectives to pursue. Some members view the agreement as vital for U.S. firms, workers, and farmers. That sets up a potential friction point with the executive branch, which has driven trade policy largely through unilateral action. The USMCA review gives Congress a formal opening to reassert its role in trade policy.
For U.S. businesses and supply chains: Mexico's deep integration into North American manufacturing, particularly in automotive, electronics, and agriculture, means that broad tariffs carry real disruption risk. Mexico has 13 free trade agreements covering more than 50 countries, making it a globally connected production hub. Companies that built supply chains around USMCA compliance have an incentive to maintain that status to avoid the 10 percent tariff, but uncertainty about the agreement's future makes long-term planning difficult.
For Mexico: The bilateral trade negotiations playing out now are happening against a backdrop of legal volatility on the U.S. side. Mexico enters the USMCA Joint Review knowing that the tariff tools the U.S. has deployed against it are legally contested and time-limited, which may shape its negotiating posture.
The Bottom Line
The CRS report on U.S.-Mexico trade relations captures a relationship under pressure from multiple directions at once. The administration's tariff authority has been curtailed by the courts, its replacement tool has an expiration date, and the trade agreement that governs nearly $1 trillion in annual commerce is up for review.
Congress has a narrowing window to shape what comes next. The USMCA Joint Review is the most immediate lever, and the CRS report signals that members are aware of it. Whether Congress engages substantively or leaves the administration to drive the outcome will determine how much legislative input goes into the next chapter of North American trade policy.
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