University of Michigan economist Justin Wolfers has a warning about President Donald Trump's ban on diesel exports: it could leave the country short on supplies it needs.
Wolfers laid out his case in a video for his newsletter, Platypus Economics, and shared it on X Saturday. He said three "boring questions" expose the policy's flaws: "can it be stored, what else is made with it, and are we creating supply?"
"Those punch three big holes in Trump's diesel export ban," he wrote.
In the video, Wolfers argued that the policy will make foreign buyers stop seeing American fuel as dependable.
"If foreign buyers learn that American diesel comes with a political cancellation clause, they're going to go looking elsewhere," he said.
He said the damage won't end with lost sales. Countries hurt by the ban could look for ways to hit back, and China already has one. Beijing has restricted exports of rare earths and other critical materials during past trade fights. Those minerals end up in "our cars, our semiconductors, our advanced weapons," Wolfers said.
"China's not going to need to cut off every shipment to make its point," he said. "It just needs to remind American firms that two can play at this game."
Wolfers compared the ban to the first round of Trump's trade war. In that round, U.S. import restrictions led other countries to retaliate with restrictions of their own.
"Now we're restricting exports," he said. "The end game of all this is we may not get the supplies we need."
He said his view doesn't come from personal preference.
"You get the sense that I think a ban on exporting diesel is a really bad idea. But it's not me — it's the basic economics of it," Wolfers said.
He said anyone who claims keeping diesel at home will lower prices should be asked whether the policy "create[s] more supply, or does it just rearrange scarcity?"
"We don't need to rearrange scarcity here," he said. "We need to solve it."
Ask three boring questions: can it be stored, what else is made with it, and are we creating supply? Those punch three big holes in Trump's diesel export ban https://t.co/daUK9IBaVFpic.twitter.com/chIjlIjSxi
— Justin Wolfers (@JustinWolfers) September 26, 2026