Abstract
We study the macroeconomic and trade-policy implications of disruptions to U.S.-bound shipping routes. Standard models treat them as iceberg-cost shocks, conflating the shock with the response to it. Using satellite vessel-tracking data, we construct route-level measures of potential and effective capacity for all U.S.-bound container ships from 2016 to 2025. Uti-lization losses in recent disruptions ran 20 to 40 percentage points, and began months before port congestion became visible. We embed these measures in a general equilibrium model in which firms reallocate a common fleet without internalizing the congestion they create and price above marginal cost, while importers’ sourcing responds to route profitability. The reallocation triggered by a disruption then has first-order welfare effects, and the route’s Do-mar weight is not a sufficient statistic for its welfare cost. The 2021 West Coast crisis and the 2023–2024 Red Sea attacks cost 0.69% and 0.35% of output. Naval protection of Red Sea shipping generated benefits of 0.04–0.08% of output at a fiscal cost of 0.02%. Tariffs decongest the routes they tax, offsetting or even reversing their conventional welfare cost.