The mechanism. The Jones Act of 1920 requires that cargo moving between two U.S. points travel on vessels that are U.S.-built, U.S.-flagged, U.S.-crewed, and U.S.-owned. It has survived roughly a century of repeal bills, GAO cost studies, Cato Institute campaigns, and a 2026 Hawaii lawsuit — all dismissed or defeated. Even when Washington reached for the law's own escape hatch this year, it proved the point: on March 17, 2026, DHS granted a Department of Defense-requested waiver covering roughly 659 energy and fertilizer commodity categories, driven by Iran-conflict supply disruptions. It expired May 17 and was extended 90 more days — but it covered fuel cargoes, not container trade, and left the domestic cabotage regime for Hawaii, Alaska, Guam, and Puerto Rico fully intact. Congress didn't touch the core law. It never does. That's the trade: a bipartisan coalition of maritime unions, U.S. shipyards, and national-security hawks has held for a century, and the companies sitting inside the moat collect toll regardless of who's in the White House.

Who cashes in. MATX (Matson) is the mechanism's purest expression — roughly half its ocean transportation revenue comes from Jones Act-protected Hawaii and Alaska trades where it faces limited direct competition, giving it pricing power and cash flow durability no foreign carrier can contest no matter how many container ships they operate. Matson is now plowing that protected cash into three new "Aloha Class" dual-fuel ships for Hawaii, Guam, and China-Long Beach routes — a fleet renewal only economical because the lanes it serves are legally closed to outside capacity. HII (Huntington Ingalls) and GD (General Dynamics) benefit from the adjacent policy logic, not the same statute: the same national-security argument that sustains Jones Act cabotage — that America must retain a domestic shipbuilding and mariner base — underwrites Navy and Coast Guard shipbuilding budgets at their yards, and any renewed "maritime renaissance" push in Congress (tax credits, MARAD funding, sealift subsidies) tends to lift naval and commercial yards together. BWXT and LDOS sit further out on that same national-security-industrial-base thesis — nuclear propulsion components and fleet-support/logistics services that ride the same bipartisan appetite to keep American maritime capacity alive.