Speaker Mike Johnson, Majority Leader Steve Scalise and 50 other House Republicans just signed a letter asking President Donald Trump to allow the ongoing waiver of the Jones Act, a protectionist shipping law, to expire as scheduled on Aug. 16.

They are effectively calling for higher energy prices.

The Jones Act, passed in 1920, requires that ships transporting goods between U.S. ports be U.S.-built, U.S.-flagged, U.S.-owned and U.S.-crewed. Given that the modern maritime industry is highly globalized, few ships meet those conditions, and the ones that do are very expensive. The law severely constrains U.S. coastwise trade.

That especially harms the U.S. energy industry, which needs to transport fuel feedstocks and finished products between different regions of the country. That’s why Trump waived the Jones Act on March 17, amid the Iran war, to help alleviate price pressures caused by the conflict.

The Jones Act is frequently waived during natural disasters when it would hinder the transportation of relief supplies, but the ongoing 150-day waiver is the longest in recent history. In this real-life experiment of what life would be like without the Jones Act, the results have been excellent.

The Cato Institute counts 136 voyages of foreign ships between U.S. ports under the waiver, as of June 25. The most common good transported has been gasoline, nearly 10 million barrels, according to government data.

Some regions are seeing especially strong benefits. “In the waiver’s first 70 days, more gasoline and jet fuel were moved from the Gulf Coast to the West Coast than in the entirety of 2020-2025,” Cato found. Puerto Rico has been able to buy U.S. propane, which it normally cannot, because no liquefied petroleum gas tankers comply with the Jones Act.

These voyages have not replaced any demand for domestic ships. The Jones Act-compliant fleet remains fully booked. These are all extra voyages, connecting American suppliers with American buyers, that are normally prohibited by federal law.

Contrary to fearmongering about a Chinese takeover of shipping without the Jones Act, only one of the 136 voyages was by a Chinese-flagged vessel. The most common flags sailing under the waiver are the Marshall Islands, Liberia and Singapore.

Yet the 52 House Republicans say the law must come back into force because the waiver “has become a loophole exploited by adversarial countries to erode America’s maritime dominance.”

Such dominance does not exist despite — or perhaps because of — over a century of protectionism.

Why any politician would want to sign their name to something that would raise fuel costs right now is hard to imagine. A December 2023 paper estimated that repealing the Jones Act would reduce East Coast gasoline prices by 63 cents per barrel and diesel prices by 82 cents per barrel, saving consumers $769 million per year.

It’s revealing that only 52 out of 218 House Republicans have reportedly joined a letter that both the speaker and majority leader signed. Other Republicans, including Sen. Mike Lee (Utah) and Rep. Tom McClintock (California), have introduced legislation to repeal the Jones Act.

Energy Secretary Chris Wright called the waiver “enormously helpful” last month. National Economic Council Director Kevin Hassett has called it “incredibly effective.” Interior Secretary Doug Burgum said it would “reduce price volatility for American families.”

Letting the waiver expire will only be good for the country if it happens because the law has been repealed.