A study of nearly 600 homicides of police officers over a 14-year span ending in 2021 disputes a common belief that an ideologically driven "war on cops" is to blame for a great deal of violence against police. The study in Police Quarterly by Jesse Norris, a criminal justice professor at the State University of New York at Fredonia, found that of the 12% of police homicides that were ideologically motivated, just 3% constituted terrorism and 3% had left-wing motives. Right-wing motives made up the other 6% of ideologically motivated homicides of police, according to the study, which was based on data from the Officer Down Memorial Page and public reports on incidents, including news stories, court decisions, and government reports. "There is no evidence that BLM [Black Lives Matter] unleashed a 'war on cops' in which officers are increasingly targeted in ideological homicides," the study concludes. The study excluded cases involving correctional officers.
After the 2014 protests against police brutality in the wake of the Ferguson, Mo., killing of Michael Brown, ideological civilian-on-police homicides per quarter increased, but to a statistically insignificant degree. "While some analyses show a significant post-Ferguson increase in killings motivated by hatred for police, this is unlikely to represent a real trend due to reporting effects, and the offenders’ hatred appears unrelated to outrage about police shootings," Norris wrote. "Civilian-on-police homicides motivated by left-wing ideology and unrelated to personal revenge did significantly increase after Ferguson. Yet this accounts for a small proportion of post-Ferguson civilian-on-police homicides (4%), and most of these offenders were influenced by far-right ideology and mental illness as well." In a thread on Twitter reacting to the study, criminology professor Justin Nix of the University of Omaha wrote that he and colleagues wrote a forthcoming paper showing a spike in fatal and non-fatal shootings of police following the murder of George Floyd in 2020. Norris' study was limited to homicides.