Last month I wrote about The Great Foreign Aid Experiment of the Trump administration. Foreign aid has not been without its critics because it is inefficient, promotes corruption, or is a part of an insidious program of neo-colonialism. The decision, however, by the US Government to put foreign aid “through the wood chipper” sets up a natural experiment to test whether aid save lives—more precisely, whether the sudden removal of aid ends lives. Most people in global health believe that it will result in significant suffering, although some see a silver lining: deaths among the poor and vulnerable will mark the emergence of independent health systems in low-income countries that are more resilient and finally free of external interference.
Not content with one natural experiment at the expense of the global poor, on the 2nd of April 2025, Donald Trump announced the imposition of the highest rate of tariffs on US imports in almost 100 years. In effect, the government is dismantling the free-trade mechanism that has been operating since the mid-1990s, and adopting a more isolationist market posture. Under this new theory of trade, wealth is not created, it is finite and accrued by one country to dominate another.
The evidence has been pretty clear about the effects of poverty on health. Poor people are more likely to die than rich ones. Infant, child, and maternal mortality rates are significantly higher among the poor. Preventable and treatable diseases such as HIV, tuberculosis, and malaria also disproportionately infect and kill the poor. These poverty effects occur both within and between countries. Furthermore, they are not just biological outcomes—they are deeply social, economic, and political in nature. The conditions of poverty limit access to healthcare, nutrition, education, and safe living environments.
Over the last 75 years, in parallel with increasing life expectancy across the globe, wealth has also increased. The proportion of people living in extreme poverty today is much lower than it was 50, 20, or even 10 years ago. In fact, historically the sharpest global decline in extreme poverty occurred between 1995 and 2019—2020 was, of course the COVID pandemic, which reversed a wide rage of health and economic indicators.
Bill Clinton assumed the presidency of the United States in January 1993. He was supportive of free trade and the Uruguay Round of of the General Agreement on Tariffs and Trade (GATT), which was completed in 1994. The successful conclusion of GATT led to the creation of the World Trade Organization (WTO) in January 1995.
Following the liberalisation of trade, global extreme poverty rates fell from 36% to 10% between 1995 and 2018. In South and South-East Asia the extreme poverty rates fell from 41% to 10%. In Sub-Saharan Africa, the extreme poverty rates fell substantially, but without the same speed or depth as elsewhere: 60% to 37%. The gains of trade liberalisation were also more advantageous to some markets than others, and it particularly benefited countries with cheap manufacturing capacity such as Bangladesh and Cambodia.
The sudden US reversal on tariffs will be punishing for those poor countries that have developed a manufacturing sector—particularly in shoes and garments—to provide cheap, volume goods based on low labour costs. Of course, the goods in the US need not be cheap, because there is considerable profit in branding.
If exports drop significantly, factories will want to cut staff numbers swiftly to retain their commercial viability. Poor households, particularly those reliant on a single income manufacturing jobs, will likely be thrown backwards into extreme poverty. The global economic gains of the last 30 years could begin to reverse. A major drop in exports will have an immediate impact on the factories’ labour force but there will be flow on effects to the entire economy of poor countries. In Bangladesh, for example, garment manufacturing is the single biggest source of export revenue, and reductions here will mean reductions in national tax revenue which supports health, education and welfare services.
In other LMICs that are less reliant on a global export market, shifts in tariffs will have a concomitantly smaller impact. Thus, the two natural experiments will intersect. The impact of foreign aid on health and the impact of foreign trade on health will play out with interacting effects.
Needless to say, none of this was ever framed as an experiment. Cutting aid and raising tariffs was all to “Make America Great Again”. It is a cruel, indifferent approach to trade and foreign policy. There will be no one in the Situation Room plotting a Kaplan-Meier survival curve. No policymaker will announce that the hypothesis has been confirmed/rejected: that wealth, when withdrawn or walled off, leaves people dead. Nonetheless, the data will tell its own story.
And when it does, it won’t speak in dollars or trade deficits. It will speak in the numbers of anaemic mothers, closed clinics, empty pharmacies, and missed meals. It will speak in children pulled from school to help at home. It will speak in lives shortened not by biology, but by policy
The Great Trade Experiment, like the Great Aid Experiment, won’t just test theories in global health and economics. It will test people—millions of them. And the results, while statistically significant, will not be ethically neutral. Some experiments happen by accident. Others, by design.
This one was designed—by the President of the United States.