“It felt like vertigo”: The White House used this economist’s research to justify tariffs. They couldn’t have got it more wrong

Earlier this month, a top White House economist made headlines by citing an Ontario-based academic’s research to justify Donald Trump’s latest volley in the trade war with China: sweeping tariffs on Chinese imports, which surpassed 245 per cent on April 15. But Pau Pujolas, the McMaster professor behind the paper in question, says the Trump administration cherry-picked his work to justify a policy it was never meant to support. Here, Pujolas explains how it felt to see his research twisted by US policy makers and why he thinks tariffs are always a bad idea.

Let’s start with your reaction. How did you find out that the Trump administration was citing your research? I heard about it right after a basketball game, of all things. I play in an amateur three-on-three league in Hamilton, and we’d just won our semi-final. As I was getting changed, I saw a message from Timothy Kehoe, my mentor and an economist at the University of Minnesota. He wrote, “You’re famous—and I don’t think you’re going to like it.”

He sent me a link to a speech by Stephen Miran, Trump’s economic adviser. Miran had just cited a paper I co-authored. At first, it felt like vertigo. On the one hand, I thought, “Wow, I wrote something that matters.” But, on the other, the policy being pushed had nothing to do with what I argued. It was clear they’d taken one line and ignored the rest of the paper. We might be witnessing the biggest collapse in global trade since the Second World War, and suddenly my name was linked to it. It wasn’t a pleasant feeling.

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For those who haven’t read your paper, what was its central argument? First, let me be clear: trade wars are bad, always and everywhere. My paper looked at the 2018 US–China trade war and showed that, under very specific conditions—and I really stress very specific conditions—countries with large trade deficits, like the US, may be tempted to impose tariffs and could see very modest welfare gains as a result. But that wasn’t a recommendation. The paper also explains that those modest gains come at a higher overall cost—both to countries on both sides of the trade war and to the global economy. We wanted to send a message to policy makers saying, “Yes, trade deficits may entice you to do something like tariffs, but don’t give in to that temptation.”

So, in other words, your paper was a warning, but the Trump administration took it as a green light? Exactly. The paper says, “Let’s be very careful.” But their logic was, “See? A trade deficit means we can start a trade war—so let’s start one.”

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As an academic, do you have any recourse when your research is being misused or taken out of context? Not really. Once the research is published, how it’s perceived and used is largely out of my control. I didn’t contact anyone in the Trump administration about it, and no one reached out to me either. I’ve given every interview I’ve been asked to do about the situation, and I’ve clearly and repeatedly explained that my work has nothing to do with what Trump is doing. I can’t do more than that.

Beyond its selective reading of your paper, are there other things the Trump administration’s economic policy got wrong? In 2018, during Trump’s first term, the US didn’t implement tariffs in the way my models suggested might lead to minor gains. They targeted the wrong sectors and used the wrong magnitudes. If they had calibrated everything just right, they could’ve improved their position ever so slightly—while harming their economy in the long run. But they didn’t, and they lost the 2018 trade war. And now, in 2025, what they’re doing is even worse. A 245 per cent tariff is absurd. There’s absolutely no scenario in which that number makes sense. It’s going to hurt everyone—especially Americans.

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What will that hurt look like? American consumers will pay more for goods from China. US firms that rely on Chinese inputs for their operations will see costs spike. Some of them will go out of business, and workers in those firms will lose their jobs. On top of that, American companies that export to China are going to suffer by paying China’s retaliatory tariffs. Then it cascades. Businesses stop hiring. Households tighten their belts. That hits restaurants, retailers, building developers—everyone.

Will the effects of the US–China trade war ripple out into Canada? Absolutely. We’re deeply linked through supply chains. It’s not just the tariffs themselves—it’s the uncertainty created by the whiplash of Trump saying 20 per cent one day, then 10 per cent the next, then pausing them, then doubling down. Just look at what’s happening right now in Ingersoll, Ontario. GM announced temporary layoffs of hundreds of workers at its plant there, and that’s directly connected to uncertainty caused by Trump’s global trade policies. Canadians will suffer even if they’re not the primary target.

Is there any legitimate economic case for tariffs? In one word: no.

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Then why do governments around the world keep imposing them? Tariffs are popular because they’re easy to implement—just slap them on at the border. Put simply, tariffs are a terrible policy in every context because they impede trade and raise costs. They impoverish everyone for the marginal benefit of specific industries or companies. One silver lining from this ongoing trade war is that people will get first-hand evidence of how bad tariffs are. Hopefully, people will be a little more receptive to the idea of opening up borders to the free flow of goods and services. The sooner we move toward a world without tariffs, the better off we’ll all be.

Some people will still argue that tariffs help protect local jobs. You often hear things like, “We used to build our cars here, but now they’re made overseas where labour is cheaper.” How do you respond to that kind of reasoning? Stop thinking in terms of “protection.” You don’t fix economic problems by raising tariffs and increasing costs for everyone. We should be helping firms grow strong enough to compete globally, not shielding their weaknesses. And the best way to support your workforce is by investing in what societies need to flourish: things like education, health care and a strong rule of law so citizens aren’t subject to the whims of monopolies and cartels.

Long before this trade war, Canada used tariffs to protect certain domestic industries like dairy. What would you say to those who argue that these policies are essential to supporting people like dairy farmers? And what would you propose instead? Tariffs on dairy products make life more expensive for all of us—and they do it to benefit a small group of producers. Take the example of someone who just lost their job at the GM plant in Ingersoll. That worker has spent their entire life paying inflated prices for milk and cheese. And now, they’ve also lost their job as a result of the tariffs in this trade war. We don’t need to support industries through tariffs. We need to open markets and let talent and investment flow to the most productive parts of the economy. If a business can survive only because it’s shielded by government policy, that’s a sign that the business shouldn’t exist in its current form.

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Have you received any backlash since your paper was cited? I’ve seen some criticism online—people blaming me for what’s happening or dismissing me as an “obscure” researcher. But I don’t take it personally. People are angry and looking for someone to take their frustration out on. I’ve been clear and transparent about what my paper actually says, and anyone can read it for themselves.

Has this experience changed how you think about publishing research that intersects with politics? Not really. This will all blow over. I’m looking forward to going back to being anonymous again.

What are you working on now? I’m studying the new tariffs Trump has been announcing all year—evaluating how bad they are for the global economy and for the US in particular. Spoiler alert: they make no sense.

This interview has been edited for length and clarity