Ana Swanson
On January 26, 2025, Jamieson Greer was teaching Sunday school to a group of nine-year-olds when one of his phones started blowing up with calls from the White House. Six days into the new administration, President Donald Trump was already deploying his favourite weapon: the threat of crippling tariffs to bend countries to his will.
Greer would not join the Trump administration for some time yet, but he was already a key adviser on trade.
“Why do you have two phones?” a student asked him.
“I have a kind of crazy job,” Greer replied.
As the United States trade representative, Greer, 45, has been a powerful but behind-the-scenes force in transforming the global economy. Few have done more in Trump’s second term to put into practice the president’s vision of altering the system governing how trillions of dollars of goods move around the world.
Greer has provided the legal and policy framework to overhaul a global system Trump slams as unfair. He has helped the president raise tariffs to their highest levels in nearly a century while simultaneously leading negotiations with all of America’s biggest trading partners.
Interviews with Greer make clear that he is a true believer in Trump’s plan to use tariffs to revitalise the US manufacturing sector. He and other advisers have ushered in steep import taxes to try to protect manufacturers from foreign competition, coax more factories into the US and create more good-paying factory jobs.
It’s not yet clear those initiatives will work. Manufacturing employs less than 10 per cent of Americans, and the number of factory workers has been dwindling. While some manufacturers support protectionism, others say it raises their costs and makes US industry less competitive. Consumers are also concerned about tariffs causing price increases, and polls show Trump losing support for his handling of the economy.
Although Greer credits the president’s tariff threats with giving him leverage in negotiations, Trump’s penchant for brinkmanship has clearly added uncertainty and complications to how countries deal with the US.
This year seems likely to bring more tumult, as the Supreme Court reviews whether to overturn many of these tariffs. The administration is also preparing for high-stakes meetings with China, and negotiations with Canada and Mexico that could transform or dissolve the North American trade deal.
Greer is often seen as a source of stability in the chaos. A former Mormon missionary and military lawyer, he has quietly navigated the demands of an unpredictable president, other big personalities in the cabinet, and dozens of foreign leaders and company executives. Friends say he has followed the advice of his mentor and former boss, Robert Lighthizer, who served as the US trade representative in Trump’s first term: “You can get a lot done in Washington if you don’t care who gets the credit.”
Greer was set on a path towards his future role as the architect of Trump’s trade strategy by what he called a “serendipitous” interview with Lighthizer for a job in Washington at the law firm, Skadden Arps. Lighthizer said Greer had impressed him as someone with “brains and values”, and hired him in 2012 to help the firm defend US Steel and other American companies in trade cases.
That work gave Greer an advance look at what US industries would face in the coming years, as Chinese exports heavily subsidised by Beijing flooded global markets.
Greer saw the influx of cheap goods as a national security issue, but few agreed. That changed with Trump’s election in 2016, when Lighthizer became US trade representative and appointed Greer as his chief of staff.
Greer became Lighthizer’s shadow. To the surprise of foreign bureaucrats, Lighthizer sent the then-30-something Greer in his place to high-level meetings with the World Trade Organisation, South Korea and Mexico. Together, they waged a trade war against China and reworked the North American Free Trade Agreement.
The administration had done as much as it could in the first term, Lighthizer said, but since then, the country’s views on trade have shifted, and the president now has an even stronger mandate.
“The president is taking the next logical steps and Jamieson is the best possible person to implement it,” he said.
After Trump left office, Greer went into private practice. And when the president won in 2024, Greer helped compile lists of trade loyalists for the new administration and drafted a trade memo that the president issued on his first day back in office, which teed up the possibility of tariffs to address more than a dozen trade issues.
Lighthizer threw his weight behind Greer’s appointment. The decision was supported by Jared Kushner, Trump’s son-in-law, and others who thought the president would be better served by a trade expert in cabinet than another billionaire.
By the time Greer was confirmed on February 26, 2025, Trump was already wielding tariffs with abandon, in ways that were more chaotic than Greer might have preferred.
Out of all the options he could have used to impose tariffs, Trump chose an international emergency law that would let him immediately raise or lower tariffs, and keep them in effect as long as he liked.
But the law, the International Emergency Economic Powers Act, was vulnerable to legal challenges, which was one reason Lighthizer had not used it in Trump’s first term. Greer also saw it as more legally vulnerable than other options, but he had included it in the options he presented to Trump, and said Trump chose it because of its flexibility.
In February 2025, Trump used the law to declare inflows of fentanyl a national emergency, and to deploy tariffs against Canada, Mexico and China, the largest trading partners of the US.
In April, Trump used the same law to declare trade deficits an emergency. He announced sweeping global tariffs as high as 50 per cent, including tariffs of 34 per cent on China, a move that set off a trade clash that remains unsettled.
The trade representative’s office was immediately inundated by requests from foreign officials seeking to avoid the tariffs. That kicked off months of furious negotiations for Greer, who flew more than 160,000 kilometres in 2025 and sometimes met representatives of more than half-a-dozen countries each day.
Given the hurried timeline, Greer created a template of issues for countries to negotiate on. The resulting deals involved countries dropping their tariffs on US agriculture and industrial goods, and the adoption of other policies aimed at non-market economies like China.
Many of the agreements ended up vague and high level, reflecting the rushed pace of the talks. Governments would later clash with the US over the exact details.
Few have done more in Trump’s second term to put into practice the president’s vision of altering the system governing how trillions of dollars of goods move around the world.
Talks were also complicated by the fact that countries were subject to another set of national security-related tariffs that were the domain of Commerce Secretary Howard Lutnick. Those tariffs affected sectors such as cars, pharmaceuticals and steel. Foreign countries complained that negotiations proceeded smoothly with Greer, but hit roadblocks with the Commerce Department.
Greer said in an interview that “tensions” was “not a word I would ever use” but acknowledged the national security tariffs had added “an extra layer of complexity”.
The coming year could bring more challenges for Greer.
If the Supreme Court strikes down Trump’s tariffs, Greer will be the one responsible for instituting other tariffs to replace them. He will also need to ensure trade arrangements struck with Japan, El Salvador, Switzerland and other countries don’t unravel if the tariffs that undergird those deals temporarily disappear.
With midterm elections approaching and concerns about affordability growing, it also remains to be seen if the administration walks back more tariffs.
Trump seems as insistent about tariffs as ever, and as impulsive in their use. Last month, he threatened tariffs against European nations unless Denmark gave him Greenland. The Europeans responded by angrily pausing work on their trade deal, which Greer and his deputies had spent many months negotiating.
Like Trump, Greer dismisses the idea that tariffs burden poorer Americans. He argues, instead, that the cost of tariffs is being spread through foreign supply chains, something many economists dispute. He also defended the idea of “managed trade”, saying that the more secure supply chains were, the less the government needed to intervene. “But we’re not really there yet,” he said.
This article originally appeared in The New York Times.
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