Americans living in political "swing states" have a significantly louder voice in national trade policy - effectively making their votes worth more than others - according to a new study published in the Journal of International Economics.
Professor Karim Chalak from The University of Manchester, Professor John McLaren from the University of Virginia and Professor Xiangjun Ma from Liaoning University found that US governments of both parties tend to shape their trade policies to favour industries based in states that could decide presidential elections.
Using decades of economic and political data - from the Clinton years through to the Trump trade wars - the team found that US tariffs are consistently biased toward industries located in swing states such as Florida, Pennsylvania and Wisconsin.
According to their estimates, the welfare of a voter in a non-swing state is treated as being worth just 82 percent of that of a voter in a swing state when national trade decisions are made.
"Our research reveals the extent to which US policymakers cater to the welfare of swing-state workers relative to others with similar jobs elsewhere," explains Professor Chalak. "This bias is a byproduct of the US's electoral system - economic policies are shaped partly by political geography."
The researchers describe how this pattern was illustrated clearly in the 1990s, when the Clinton administration negotiated special tomato trade protections for Florida ahead of a tight election. Similar patterns reappeared during later trade disputes involving steel and manufacturing tariffs.
"People often claim that the Electoral College protects small states, but the evidence is that it just penalizes people for not living in a swing state," said Professor McLaren, "and even for swing states, the best evidence is that small states do not benefit from the bias."
By combining theoretical modelling with real-world data on tariffs, industries, and voting patterns, the team developed what they call the "Swing-State Theorem." The theorem predicts that in majoritarian systems like the US, policy naturally tilts toward the interests of swing regions - even without explicit lobbying.
The findings shed light on how political incentives can distort economic policy in ways that are both inefficient and hard to justify as fair, and they may help to explain why trade wars and protectionist measures often appear inconsistent with broader national welfare. The authors suggest the same logic could apply to other areas of policy, from infrastructure spending to defence contracts.
