Americans would be hard-pressed to find a protectionist law that has inflicted more harm than the outdated Jones Act. Passed in 1920 (with antecedents stretching back to the late 1700s), the law restricts domestic waterborne transport to vessels built in U.S. shipyards and registered under the U.S. flag. Ships that comply with the law are far fewer in number, approximately four times more expensive to operate and four to five times more expensive to build than internationally flagged ships.

That combination means inflated transportation costs that stifle commerce and tilt the playing field against American businesses.

Jones Act shipping is so expensive, for example, that U.S. refineries often purchase crude oil from Saudi Arabia and Nigeria rather than Texas. Similarly, the law has been identified as a key factor for why Americans use steel from Asia instead of domestic sources, consume rice from China instead of U.S. farmers and purchase lumber from Canada instead of the Pacific Northwest.

But the Jones Act’s economic damage goes further. Expensive shipping means more demand for land-based transportation alternatives, producing more traffic, highway maintenance and pollution. The law’s rank protectionism also roils trade relations, leading to fewer export opportunities.

Jones Act supporters claim that the law ensures shipyards, ships and mariners are available to meet U.S. national security needs. The reality, however, is quite different.

Under Jones Act protectionism, U.S. shipyards have become technologically inferior and horrendously uncompetitive. Demand for U.S.-built vessels is so tepid — virtually non-existent outside the captive domestic market — that U.S. shipyards account for just one-tenth of one percent of global output. Last year, they did not deliver a single oceangoing cargo ship.

Forcing Americans to pay stratospheric prices for new ships, meanwhile, has proven a poor means of developing a healthy merchant marine. Since 1980, the number of Jones Act-compliant ships has more than halved as the fleet has become relegated to domestic trade routes where transportation alternatives such as trucking, rail and pipelines are unavailable (e.g., between the mainland and Hawaii, Alaska and Puerto Rico).

Where the 1920 law has succeeded is in generating business for Chinese state-owned shipyards used to maintain the fleet’s aging ships and lobbyists that ensure the law remains in place.

The Jones Act stifles the country’s prosperity and fails to meet its defense requirements. It’s long past time to scrap this rusted-out hulk of a law and develop a maritime policy rooted in 21st-century realities.