Lead, Lost IQ Points, and the Politics of Grievance

For decades, lead was in everything: gasoline, paint, pipes, soil. It coated playground dust, clung to car exhaust, and lingered in the homes where millions of American children grew up. We now know what that meant: a mass, population-wide poisoning. A 2022 Duke study estimated that half of living Americans were exposed in childhood to levels of lead high enough to blunt their IQ—costing the nation nearly 824 million IQ points.

This wasn’t just about school test scores. Lead is a neurotoxin that stunts brain development, weakens impulse control, erodes attention span, and increases anxiety and aggression. It reduces what social scientists call institutional efficacy—the belief that collective action or civic engagement can solve problems. In other words: lead made us less trusting, more reactive, and more vulnerable to grievance politics.

From Poisoned Brains to Polarized Ballots

The science is clear: lead exposure causes permanent cognitive and behavioral harm. What’s speculative—but increasingly plausible—is that those harms didn’t just shape individuals. They helped tilt whole cohorts, and even regions, toward certain political outcomes.

Think about the traits most strongly associated with early-life lead exposure:

• Lower political knowledge. If your cognition was diminished before you even hit kindergarten, you’re less likely to follow complex political debates or policy detail later in life.

  
  

• Higher distrust. Lead-exposed populations show elevated anxiety and reduced social trust. In politics, distrust maps neatly onto hostility toward institutions, experts, and government.

  
  

• Grievance sensitivity. Studies link lead to heightened aggression and emotional reactivity. Politically, that translates to attraction toward leaders who amplify anger and resentment.

  
  

• Lower institutional efficacy. If you believe systems can’t be fixed, you’re more vulnerable to apocalyptic or authoritarian narratives promising to blow them up instead.

Now overlay those patterns with modern U.S. politics. Who has spent the past decade weaponizing distrust, grievance, and hostility to institutions? Donald Trump and the far-right GOP.

Why Geography and Cohort Matter

The heaviest gasoline-lead exposures came in the mid-20th century, when highways slashed through cities and traffic was thick with leaded exhaust. The children most affected were born in the 1960s, ’70s, and early ’80s. Those same cohorts entered adulthood with, on average, lower cognitive resources than they should have had—and they came of political age right as U.S. manufacturing collapsed and partisan polarization deepened.

It’s not hard to see the overlap: Rust Belt counties with high historic traffic density and aging housing stock—prime lead exposure zones—are also the regions that later swung hard to Trump. Flint, Michigan, became the nation’s lead-poisoning cautionary tale, but the truth is the entire industrial Midwest was drenched in airborne lead decades before Trump ever descended that golden escalator.

A Hypothesis Worth Testing

To be clear, no peer-reviewed study has yet shown that lead exposure directly explains Trump’s voter base. But the hypothesis is strong enough to demand investigation. Political scientists already know that environmental disasters and air pollution can influence voting and turnout. Researchers have documented that the Flint water crisis depressed local participation. Studies in Europe show air pollution exposure nudges voters toward anti-establishment parties.

Why wouldn’t the largest environmental neurotoxic exposure in U.S. history—leaded gasoline—leave political scars too?

The Political Legacy of Lead

Lead didn’t just shave points off IQ scores. It may have shaved points off democracy itself. By undermining the very cognitive and emotional foundations of civic life, it likely left entire generations less equipped to resist authoritarian appeals.

If this link proves true, then America’s current crisis of polarization and Trumpism isn’t just the product of bad actors or bad media. It’s also the lingering echo of policy failure—our government letting corporations profit from poisoning kids for half a century.

The legacy of lead is still in our soils, our water pipes, and maybe in our politics. The question now isn’t just whether we clean it up—but whether we finally reckon with how deeply it already shaped who we are, and how we vote.

Sources:

• McFarland, M. J., et al. “Half of US population exposed to adverse lead levels in early childhood.” PNAS (2022).

• Duke Population Research Institute (2024). “20th Century Lead Exposure Damaged American Mental Health.”

• Hunnicutt & Henderson (2022). “Air Pollution and Political Participation in the United States.”

• López/Santiago (2023). “The Effects of a Bad Government on Voter Turnout” (Flint crisis turnout).