Noticing “substantial decline in gun violence” since the Supreme Court’s Bruen ruling

I recall a number of public health researchers and others expressing concern back in summer 2022, right after the Supreme Court’s landmark Second Amendment ruling in Bruen, that new changes and challenges to gun control laws could possibly contribute to higher gun homicide rates.  Against that broad backdrop, I read with interest this new substack posting by John Roman titled “New CDC Data Shows a Substantial Decline in Gun Violence in 2024: Gun Violence Declines are Accelerating and Greater (Local) State Capacity is the Reason.”  I recommend the full post, and here is some of the data discussion capturing my attention:

The 28.4% increase in homicide from 2019 to 2020 was the largest one-year increase in recorded history, dating back to 1960, and was almost three times larger than the prior biggest one-year increase. Homicide in the US went up again in 2021, to more than 26,000. This is roughly the same number of homicides as in 1993, which was the prior worst year for homicides in America (although there were 80 million fewer Americans in 1993, so the homicide rate was much higher).

Early in 2022, the pattern reversed, and homicide has been declining in every subsequent year. By the end of 2024, the new data show 20,157 homicides, only about 1,000 more than in 2019, the last full year before the pandemic.

Importantly, the rate of decline in all homicides and gun homicides is increasing. From 2021 to 2022, the decline was 4.5%. From 2022 to 2023, homicides declined 8.1%. And in the most recent data, 2024 homicides were 11.7% lower than 2023.

As I wrote about last year, the COVID homicide spike and decline have been almost entirely about increases in gun homicides. The new data again show that the overall decline is mainly due to changes in gun homicides and not declines in other kinds of homicide….

So, what is driving the gun homicide decline? This week, Ashley Wu and Tim Arango have a thoughtful story in the New York Times where they explore explanations for the decline. My take, in that article and here, is that this was mostly a story of state capacity. Or more specifically, a decline and then an increase in the number of on-the-ground local government employees directly interacting with young men most at-risk of violence and victimization.

I do not have any studied bases for articulating a particular theory for the encouraging trends in gun homicides over the last three years, and I am not here seeking to posit that Bruen is a large or small or any part of the recent empirical story of gun homicides.  As we all know, “correlation does not imply causation.”  Rather, I just thought these data provided another opportunity to highlight the enduring mysteries and unpredicatbilities surrounding crime trends generally, and especially surrounding the relationship between legal changes and crime trends.  (Of course, legal change is itself often mysteries and unpredicatable: the Supreme Court and lower courts have continued to uphold nearly all federal and state forms of gun control since Bruen.)