The fate of President Trump’s ambitious economic policy plans will be determined in part by the people he appoints to critical positions. With a debt of over $36 trillion (heading toward $59 trillion in 2035 by some estimates), inflation not resolved, an entitlement crisis looming and the need to extend the president’s 2017 tax cuts, we’d better hope that the cooler, more experienced heads prevail.

As it happens, Kevin Hassett, who during Trump’s first administration was chairman of the Council of Economic Advisors and later a senior advisor to the president, has been appointed to lead the White House’s National Economic Council. Clearly one of the economists Trump trusts most, Hassett might be just the person capable of charting a fiscally responsible path through challenging circumstances.

“Personnel is policy” is not just a platitude; it’s a fact that’s shaped past administrations. Key advisors have long played leading roles crafting monumental economic policies.

It’s a long list that includes Arthur Laffer during the Reagan years, whose theories on tax cuts and supply-side economics fundamentally reshaped fiscal policy and spurred growth. Ezekiel Emanuel has been called the architect of the Obama administration’s Affordable Care Act, with long-lasting impacts on U.S. healthcare.

Hassett could play an equally significant role. Take the debate about extending Trump’s 2017 tax cuts. Letting them all expire isn’t really an option, but extending them all is controversial: Tax cuts are expensive. How to pay for cuts is crucial. Unfortunately, in this populist era, corporations are often scapegoated for all that’s wrong with the world, and some voices are demanding higher corporate tax rates to pay for individual cuts.

Here, Hassett’s scholarship will prove invaluable. In 2006, he and economist Aparna Mathur co-authored the first empirical study examining the link between corporate taxes and manufacturing wages. Analyzing data from 72 countries over 22 years, they found that the burden of corporate income taxes is largely shouldered by workers through lower wages.

This conclusion has since been reinforced by many studies. In a recent review of the academic literature, Cato Institute economist Adam Michel writes: “The best economic evidence suggests that workers pay more than half, and likely three-quarters, of the cost of the corporate tax. Thus, cutting business taxes is a tax cut for working Americans.”

While there are still debates over details, it’s now well established that corporate tax cuts aren’t simply giveaways to wealthy capitalists. Having someone within the administration who is so authoritative on this issue will be essential if we’re to avoid the mistake of corporate tax hikes.

Indeed, Hassett’s work will be important in assessing which expiring tax provisions should absolutely be extended based on an ability to trigger investment, productivity and economic growth. His recent paper on the 2017 corporate tax reforms, with the Hoover Institution’s Jon Hartley and Josh Rauh, demonstrates the importance of continuing one specific form of tax relief, known as full expensing, which allows businesses to fully deduct their investments from their tax bills. That leads to productivity, growth and a more prosperous workforce.

Beyond tax reform work, Hassett has been a key researcher on how best to reduce the debt. In 2010, he and co-authors Andrew Biggs and Matthew Jensen published a paper covering more than 100 instances in which countries tried to reduce budget gaps. Governments that “addressed their budget shortfalls through reduced spending burdens were far more likely to reduce their debt than countries whose budget-balancing strategies depended upon higher taxes.”

What’s more, “the typical unsuccessful fiscal consolidation consisted of 53 percent tax increases and 47 percent spending cuts. By contrast, the typical successful fiscal consolidation consisted of 85 percent spending cuts.”

As Hassett, Biggs and Jensen made clear, a vast majority of countries that have attempted to reduce debt-to-GDP ratios have failed precisely by relying too heavily on higher tax rates. Considering that the U.S. debt and deficit are so far out of control that we must implement austerity measures sooner rather than later — it’s more a question of “when” than “if” — having someone who understands the importance of carefully designing fiscal adjustments is, once again, essential.

There are many other areas in which Hassett could be influential.

While he might believe that Trump’s tariffs can be used to get concessions from other countries, he understands that fundamentally, these are taxes imposed on Americans that pave no path to prosperity. Perhaps Hassett will temper the administration’s enthusiasm for tariffs.

Similarly, drawing on his expertise, Hassett knows that immigration is essential to economic growth — a position the Trump campaign and administration have not emphasized.

Much attention has been given to Trump’s appointees in areas like healthcare and defense. Hassett’s appointment should not be overlooked. It signals a focus on growth, job creation and even elusive fiscal responsibility — not just short-term populist measures.

Veronique de Rugy is a senior research fellow at the Mercatus Center at George Mason University. This article was produced in collaboration with Creators Syndicate.