A Brief History of Prevention Through Deterrence

The U.S. Border Patrol agency has evolved greatly over the years, shifting its focus to address changing national security concerns. It was originally established in 1924 to restrict illegal immigration by Chinese and European immigrants before moving to restrict alcohol smuggling during Prohibition. The agency adopted its current focus on illegal immigration from Mexico during the 1970s, when immigration pressures coincided with a severe economic recession in the United States. In 1994, the Border Patrol released a strategy document with the support of the Clinton administration which introduced an approach to immigration known as Prevention Through Deterrence. This tactic aimed to discourage border crossings by funneling immigrants through border entry points with harsh terrain, in contrast with previous policies based on arrest and apprehension post-entry.

Successful Prevention Through Deterrence is measured by fewer encounters and apprehensions at the border, indicating that illegal attempts to enter the country have been prevented and deterred. Barriers to entry are policed by a range of physical infrastructure like fences, vehicle barriers, and other blockades designed to stop illegal foot and vehicle traffic. These measures are supported by camera- and thermal-based surveillance systems as well as measures like deportation and criminal charges which impose legal consequences on migrants. The focus of Prevention Through Deterrence operations themselves is twofold: establishing control of high-traffic border sectors and using security measures to enable the seizure of contraband.

Presidential Deterrence Policies

Presidential administrations since Prevention Through Deterrence’s inception reflect the same commitment to preventing and deterring illegal immigration, albeit with differing approaches to this goal.

In 2003, George W. Bush formed the United States Immigration and Customs Enforcement agency (ICE), charging it with enforcing immigration law within U.S. borders and investigating cases of undocumented immigration. His 2004 update of the National Strategic Plan also included anti-terrorist measures focused on preventing the flow of weapons and set greater precedent for the use of drones, drug detection, identity verification, and baggage checking at airports.

Barack Obama’s administration saw a 2012 update of the National Strategic Plan emphasizing data collection and analysis as tools for allocating Border Patrol Resources. Obama himself also expanded deportations by implementing family detentions as a measure to deter women and children from migrating. Joe Biden’s restrictions on asylum that expedited deportation processes and allowed asylum seekers to be denied if they traveled through third-party countries without also applying for and being denied asylum in those nations.

Donald Trump’s first term saw the institution of Zero Tolerance immigration policies which prompted increases in detention and deportation capacities, due in part to the fact that they didn’t differentiate between asylum seekers and illegal immigrants traveling through the border. During this current term, he has reiterated his commitment to Prevention Through Deterrence through initiatives that will build the border wall and increase punitive capacities for immigration law violations.

Why Do Proponents Support Prevention Through Deterrence?

Figure 1: White House Release

Data from the White House Release presented in this graph indicates that immigration apprehension rates drop when the country implements stricter Prevention Through Deterrence measures. This effect has been observed throughout the 2020s with President Trump’s policies, which continue to produce encounter rates at new record lows. Internal CPB data places the November 2025 encounter rate at 30,367, 28% lower than the previous record low set only one month before. U.S. Border Patrol data has also consistently recorded an average of 10,000 encounters per month since Trump took office, 5% of the total observed during the Biden administration. Immigration CPB book-ins and detention have also dropped dramatically in 2026, falling from the high 10,000s and 20,000s during Joe Biden’s term to a range encompassing the low hundreds and 5,000s in President Trump’s second term. These declines demonstrate a consistency in the effectiveness of deterrence measures which is visible across other metrics.

Why Do Critics Oppose Prevention Through Deterrence?

International human rights organizations such as Human Rights Watch argue that Prevention Through Deterrence measures breed incredibly high disappearance and death rates. Estimates range from 10,000 to 80,000 deaths caused by Border Patrol tactics, attributing these deaths to agency procedure funneling immigrants into terrain where they are exposed to harsh climates and die from lack of aid. Reporting of these deaths has also drawn criticism from the Office of the United Nations High Commissioner for Human Rights (OHCHR). In a study on reports of known migrant deaths, the office found that language used in these announcements “naturalizes” deaths by calling them “accidental” or “natural” and listing such causes as blunt force trauma or elemental exposure. Such reporting hides the role that government agents and infrastructure play in migrant injuries. 2019 data from the San Diego Trauma Center indicates that 441 out of 455 patients treated were injured from falling off the border wall, and the design of infrastructure like the Rio Grande River buoys–which use serrated metal plates to deter migrants from climbing through gaps–increases the risk of deadly injuries.

Prevention Through Deterrence policies also create conflict in communities within patrolled areas. The Texas-based Operation Lone Star has received direct criticism for causing increases in racial profiling among immigrants and deaths among both immigrants and National Guard members. According to Human Rights Watch, the number of traffic stops in Texas’ Latin communities has increased by 92%. In the first nine months alone, there were a total of 1,046 vehicle pursuits causing at least 30 deaths and 71 injuries to immigrants, law enforcement personnel, and U.S. citizens alike.

Figure 2: OHCHR Known Migrant Deaths Along the US-Mexico Border

Conclusion

Prevention Through Deterrence is an approach to border security which has drawn bipartisan support since its creation in 1994. It has been refined over the course of multiple presidential administrations and operates by tightening border security to create harsh conditions for illegal immigrants. While proponents of the policies see them as successful because of consistently reduced encounters at the border, opponents question the larger costs of these measures by pointing to patterns of enforcement-related deaths and violence in nearby communities. The debate has drawn questions about how to achieve true prevention of illegal immigration and the metrics used to assess its success.

Caterina Guerin is a non-traditional Ada Comstock Scholar at Smith College, majoring in Government with a concentration in International Relations and a minor in Korean.

This nonpartisan policy brief, written by an ACE fellow, is republished by The Fulcrum as part of our partnership with the Alliance for Civic Engagement and our NextGen initiative — elevating student voices, strengthening civic education, and helping readers better understand democracy and public policy.