Violence risk assessment of Sovereign Citizens: An exploratory examination of the HCR‐20 Version 3 and the TRAP‐18

Abstract

Sovereign Citizens comprise an understudied right‐wing extremist movement in the United States who have grown in notoriety in recent years due to several high‐profile instances of violence. Despite this, little empirical research has been conducted on Sovereign Citizens, including research on assessing their risk for violence. In this study, we sought to replicate and extend a prior study on Sovereign Citizen violence. Using open‐source data, we added several new cases to a pre‐existing dataset of violent and non‐violent Sovereign Citizen incidents, yielding a total sample of 107 cases, 69 of which were scored using the HCR‐20V3, and 83 of which were scored using the TRAP‐18. Our findings indicated that higher scores on both instruments were significantly associated with greater odds of cases being violent. We also observed that several risk factors occurred with significantly more frequency among violent cases than non‐violent ones. Implications for future research and professional practice are discussed.

Case analysis: Application of the Terrorist Radicalization Assessment Protocol–18 to the perpetrator of the Marjory Stoneman Douglas high school shooting in Parkland, Florida.

“…Eight of the distal characteristics were identified retroactively in the case of NC. Vargen and Challacombe (2023) investigated 83 cases of violent and nonviolent Sovereign Citizen incidents, using the TRAP-18. Their findings "indicated that higher scores … were significantly associated with greater odds of cases being violent" (p. 55).…”

The Hanau terror attack: Unraveling the dynamics of mental disorder and extremist beliefs.

“…Warning behaviors should compel a sense of urgency in those assessing and risk managing subjects of concern. (p. 8) TRAP-18 research has so far indicated both high sensitivity and high specificity (Böckler et al, 2020;Vargen & Challacombe, 2022).…”

The concept of last resort in threat assessment.

“…Meanwhile, an independent research group investigated sovereign citizens, an antigovernment nationalist collective in the United States, with the TRAP-18 in two studies (Challacombe & Lucas, 2019; Vargen & Challacombe, 2023). In the first study (Challacombe & Lucas, 2019), subjects ( n = 30) who planned or committed violent actions were compared to subjects ( n = 28) who committed nonviolent criminal actions.…”

“…This was the first postdictive study of a U.S. domestic terrorism group. In the second study (Vargen & Challacombe, 2023), the sovereign citizen sample was increased to 107 cases, and the TRAP-18 was coded alongside the HCR-20 V3 Historical scale. Higher coding on both instruments was associated with greater odds of being violent.…”