“Force Multipliers” in Question: An Analysis of the Jail Enforcement Model of 287(g) Agreements and Immigration Detainers in Texas County Jails

Abstract

Local jails have emerged as central sites for immigration enforcement under the 287(g) program, which trains officers to perform federal immigration enforcement. As of December 2025, 806 sheriff’s offices across the country operated under one or more of the three 287(g) models, with 74 sheriffs adopting the Jail Enforcement Model in 2025. The Jail Enforcement Model (JEM) empowers local law enforcement to issue immigration detainers, with ICE approval, to people already in jail, holding them for pick up by Immigration and Customs Enforcement [ICE]. Federal officials describe this program as a “force multiplier” because thet reinforce the ability of ICE officers to identify and detain potentially removeable noncitizens who have come in contact with the criminal justice system. This thesis examines whether JEM adoption could be associated with differences in custody transfer percentages, defined as the percentage of issued detainers on people in jail resulting in federal custody, across 29 Texas county jails. I asked two research questions: (1) Do offices that have entered into JEM 287(g) agreements with the federal government (JEM-only) experience higher custody transfer percentages compared to non-287(g) counties? (2) What does the immigration detainer process look like in JEM-only versus non-287(g) counties in Texas? I hypothesize that JEM-only counties have higher custody transfer percentages than non-287(g) counties because of the “force multiplier” logic. To answer these research questions and test this hypothesis, I employed a mixed-methods approach, combining quantitative analysis of ICE detainer and detention data with qualitative interviews with two sheriffs, a sergeant, and four jail officers across six of the 29 counties. For the quantitative analysis, I used ICE detainer and detention data from 29 Texas counties between September 1st, 2023 and October 15th, 2025 based on the most recent ICE data available, comparing nine JEM-only counties with 20 non-287(g) counties. This analysis found that JEM-only counties and non-287(g) counties demonstrate statistically similar custody transfer percentages: 73.32% vs 78.90%, respectively. The qualitative analysis is based on six semi-structured interviews to investigate potential explanations for my quantitative findings. This analysis identified two mechanisms that might account for why JEM-only counties and non-287(g) counties experience similar custody transfer percentages: (1) Under Texas law, Texas county jails must honor immigration detainers, no matter 287(g) adoption, (2) ICE’s prosecutorial discretion to close certain cases. However, the small number of interviews and non-random selection based on access and responsiveness introduce significant limitations to generalizability. This thesis ends with a discussion of implications for understanding JEM and 287(g) as immigration enforcement policy as well as outlining avenues for future research and recommendations aimed at standardizing delegated powers and protecting vulnerable populations.