US-Mexico security cooperation has deepened significantly in 2026, with Mexican forces conducting major operations against cartels using US intelligence, including the February raid that killed CJNG leader El Mencho. This followed initial Trump administration threats of airstrikes or ground action to target fentanyl labs and trafficking networks. Bilateral ties have improved markedly by September, with US officials publicly praising Mexican efforts, expanding vetted units and intelligence sharing, and effectively shelving plans for unilateral US strikes on Mexican soil. Limited US troop training visits have been approved, while maritime interdictions continue. Traders appear to weigh sustained diplomatic and operational collaboration against any renewed unilateral pressure as key variables.