IIRC the biggest issue with the jones act is the supply of US-built vessels, which are expensive, the current fleet is aging and, outside of defence, there's no real domestic shipbuilding industry anymore. This also means that domestic shipping (especially to populated areas that are not part of the lower 48) can't use anywhere near as much in the way of modern containers. This is anecdotal, but I've heard that people in Puerto Rico and Hawaii routinely order stuff from foreign countries as even with duties, it can be cheaper than ordering it from the mainland.

The act is problematic because it hasn't really been modernized, with the handful of revisions essentially just expanding its scope. The US either has to seriously figure out getting domestic shipbuilding going again (to the point where it can be economical to also export them) or at least whitelist foreign countries (eg South Korea) to allow their ships to be used. But that's unlikely in today's political climate.

The US government used to provide differential subsidies for cargos shipped on US flagged ships. This ensured that US shipping was competitive with the bottom dollar global shippers, at least for some cargos.

This ended under Reagan.

At first lots of people didn't care because Reagan was also doing his 600 ship navy so everyone was busy doing navy work, but after that ended the MM and american shipbuilding entered a death spiral.

Now the only work US flagged vessels can get is supporting the navy, and a tiny sliver of jones act trade. This means there are no economies of scale. If a ship is built, one is built to that class not 10. Orders are highly intermittent and there is no ability to build up a skilled workforce in efficient serial production. On the seagoing side, ships either get run ragged on aggressive schedules (ex: El Faro) or they sit in layup for long stretches rusting away.

If the US wants to fix its merchant marine it needs to provide incentive for increased cargos and increased shipbuilding. As Sal points out, the US is the second-biggest shipowning country in the world. US business like owning ships, they just don't want to fly the American flag because their incentives are towards offshoring.

The incentives are also all over the place. The shipping industry uses a lot of labour from "poor" countries, but on bulk shipping the labour costs are often a rounding error. The main issue is, of course, working conditions. Americans don't want to sit on a freighter for 6 month tours away from their families. The US navy has a hard enough problem doing it for people in their early 20s, and even then that's usually to get access to education funding. People from the Philippines will do it because it is life-changing amounts of money and the alternative is abject poverty.

It is usually 3 month tours, twice a year. So 3 months out, 3 months at home. Repeat.

>"Americans don't want to...." This phrase needs to die. Americans(or any population) are not some sort of monolithic group that can only do some small subset of work.

"There are approximately 5,600 container ships operating worldwide as of early 2023"(from DuckDuckgo AI). Assuming a crew of 10 per ship; 56,000 people total are required.

"As of August 2025, the civilian labor force is approximately 171 million people."(from DuckDuckgo AI)

So to fully staff the WORLDWIDE fleet with Americans, it would take 0.03% of the labor population. This is a vanishingly small amount and since labor cost is as you say a rounding error, if it offered a competitive pay I am sure that there would be enough takers.

> Americans don't want to sit on a freighter for 6 month tours away from their families

And yet finding crews was never a problem before differential subsidies ended.

In fact crewing US flagged is harder now because the work is intermittent. If people can't find berths they time out on their licenses and go do something else in a different industry.

> People from the Philippines will do it because it is life-changing amounts of money

The international minimum wage for seafarers is about $700/mo. In comparison wages in the Philippines are between 20k-50k pesos a month or $340-$850. Seafaring is an above-average income job in the Philippines but not "life-changing."

IIUC, the only issue with the jones act requiring US-built vessels is that previous the US Navy used to buy US-built vessels and lease them out below-cost and don't do that anymore. It was never economically to use US-built vessels but we've stoped subsidizing it anymore.

The US navy did not. The US Treasury used to provide "differential subsidies" to allow US flagged vessels the ability to win cargos in international trade versus non-us flagged vessels with lower operating costs.