If you don’t follow political blogs, you may not have noticed Kevin Drum’s outstanding story about how the decrease in crime over the last 20 years can largely be attributed to the sharp drops in lead ingestion. When I first heard the theory, I thought it was too good to be true, but Kevin’s story has persuaded me. At the very least, the burden is on those who think that it is wrong, and so far, they have not put up anything.
The theory isn’t complicated: lead levels cause reduced IQ, hyperactivity, behavioral problems, and learning disabilities but they also reduce “executive function,” i.e. emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility. Lead isn’t just “bad for you”: it causes severe brain damage. And that causes severe violence. “Put it all together,” says Drum,
and you have an astonishing body of evidence. We now have studies at the international level, the national level, the state level, the city level, and even the individual level. Groups of children have been followed from the womb to adulthood, and higher childhood blood lead levels are consistently associated with higher adult arrest rates for violent crimes. All of these studies tell the same story: Gasoline lead is responsible for a good share of the rise and fall of violent crime over the past half century.
Like many good theories, the gasoline lead hypothesis helps explain some things we might not have realized even needed explaining. For example, murder rates have always been higher in big cities than in towns and small cities. We’re so used to this that it seems unsurprising, but Nevin points out that it might actually have a surprising explanation—because big cities have lots of cars in a small area, they also had high densities of atmospheric lead during the postwar era. But as lead levels in gasoline decreased, the differences between big and small cities largely went away. And guess what? The difference in murder rates went away too. Today, homicide rates are similar in cities of all sizes. It may be that violent crime isn’t an inevitable consequence of being a big city after all.
The gasoline lead story has another virtue too: It’s the only hypothesis that persuasively explains both the rise of crime in the ’60s and ’70s and its fall beginning in the ’90s. Two other theories—the baby boom demographic bulge and the drug explosion of the ’60s—at least have the potential to explain both, but neither one fully fits the known data. Only gasoline lead, with its dramatic rise and fall following World War II, can explain the equally dramatic rise and fall in violent crime.
All very well and good. But why did gasoline lead levels drop off? Oh yes — because the EPA started in 1972 to push for getting it out of gasoline! Lead had been in gasoline for decades. Manufacturers insisted that it caused no damage. They said that there was nothing else that could improve auto performance. And EPA said it didn’t care, even after it lost an initial lawsuit at the trial court level. Those terrible, awful bureaucrats basically saved large chunks of the country from a continuing disaster.
Read the whole thing. Drum makes a very good (although not airtight) case for a new effort to get rid of remaining lead in land and in residential areas. It would cost a lot — more than $10 billion a year — but will pay off many, many times over.
But of course the Republican Party will not entertain this, because of the socialist Kenyan Islamist bureaucrats who want to get rid of our freedumz and rob us of our precious bodily fluids. This is why we can’t have nice things.