Border enforcement in the United States has historically been treated as an exclusively federal responsibility. For more than a century, the federal government has exercised primary authority over immigration, foreign affairs, and international borders, and organized itself to carry out these responsibilities. Today, the federal agencies in charge of border enforcement involve the U.S. Customs and Border Protection (CBP) under the U.S. Department of Homeland Security, and its components of the U.S. Border Patrol and the Office of Field Operations. These agencies seek to regulate the entry of people and goods into the United States and to enforce immigration law along U.S. borders.

However, over the past three decades, various states have launched state-led border security efforts. In particular, Texas has transformed its borders by deploying state agencies to conduct a wide range of border enforcement, criminal prosecution, and immigration-related activities. These efforts began in 2005—as Texas launched its state operations at the border—and continue through today. Over the past five years, Texas leaders have launched Operation Lone Star to address cross-border movements and transformed state-led border security efforts throughout the state and beyond.

This report focuses on the Texas Department of Public Safety (DPS). DPS’ earliest origins in the Texas Rangers mean that it has a long history of guarding Texas’ frontiers. Yet, its contemporary role in border enforcement began only two decades ago. During this time, DPS has gradually expanded from its traditional statewide policing role into a more sustained presence along the Texas-Mexico border, which combines patrol operations, intelligence gathering, and interagency coordination. These activities have shifted how DPS conducts border enforcement and have also produced significant operational, fiscal, and political effects across not only Texas but also the federal government.

This policy report seeks to answer three specific research questions: 1) how has DPS historically engaged with border security and migration enforcement in Texas? 2) what role does DPS currently play in border security and migration enforcement, particularly as part of Operation Lone Star? And 3) what have been the outcomes and effects of these enforcement efforts? To answer these three questions, we used a mixed methods approach. Specifically, we reviewed and analyzed publicly available news articles, press releases, and social media posts, requested data and internal materials from DPS, and conducted interviews with DPS troopers, members of civil-society organizations and public policy organizations, immigration attorneys, and journalists. Taken together, this approach allowed us to gain a varied perspective on DPS’ involvement in border enforcement.