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Unintended Consequences: Three-Strikes Laws and the Murders of Police Officers

NCJ Number
Carlisle E. Moody; Thomas B. Marvell; Robert J. Kaminski
Date Published
January 2002
33 pages
This document discusses the relationship between “three-strikes” laws and police officer murders.
Three-strikes laws call for life imprisonment or extremely long prison terms if a person is convicted of a third serious crime, such as murder, rape, robbery, kidnapping, aggravated assault, and sexual assault. Twenty-four States enacted these laws that went into effect during a period of 25 months, between December 1993 and January 1996. The few studies that have explored the question of deterrence find that the laws have neither reduced crime nor increased prison population. The theoretical exploration of criminals’ reactions to the laws is more complex. Criminals might try to reduce expected costs by taking evasive actions, such as moving to other jurisdictions, switching to crimes that involve less risk of apprehension, and bribing police. This study explored the fact that criminals that believe that they face three-strikes penalties might murder police in order to escape arrest. The dataset was a pooled time series and cross section of 50 States for the period of 1973 to 1998. The dependent variable was the number of law enforcement officers feloniously killed in the line of duty. The target variable was a dummy variable that took the unit value in years following the passage of a three-strikes law. The results show an estimated impact of 44 percent more murders in years following the laws. In the average state there were 1.2 police murders per year in the 1990's; so the typical three-strikes law led to an additional police murder roughly every other year. This means that approximately 0.0006 percent of arrests for major violent crimes in three-strike States involve police murders that would not have occurred without the laws. Several other criminal justice policies that might affect police murders were evaluated by the pooled regression model. Laws requiring sentencing enhancements for crimes committed with firearms appear to reduce police killings by roughly 18 percent. The size of the prison population, the number of executions, and the presence of right-to-carry concealed weapons have no discernible impact. 1 figure, 5 tables, 52 references, appendix