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Changing Border Policies and Apprehensions: What’s the Relationship?

Encounters at the border have reached record levels in recent years. The Biden administration, like many of its recent predecessors, has tried and failed to address this issue and counter criticisms from both ends of the political spectrum. The rise in border apprehensions necessitates an understanding of the impact of border policies as Congress considers various reforms.

This blog outlines the impact on apprehension numbers of the implementation and/or termination of various immigration policies at the border during the Trump and  Biden administrations, such as the Zero Tolerance Policy, Migrant Protection Protocol (MPP), Prompt Asylum Claim Review (PACR), Humanitarian Asylum Review Process (HARP), Third Country Asylum Rule (Trump), Title 42, Family Expedited Removal Management (FERM), Circumvention of Lawful Pathways Rule (Biden), and the Cuban, Haitian, Nicaraguan and Venezuelan Parole programs. There is significant overlap of many of these policies, and some, like MPP, were stopped and re-started by litigation during this time period resulting in inconsistent border policy.

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Summary of Policies

This chart provides an overview of significant policies enacted between Fiscal Year 2014 and Fiscal Year 2023.

PolicyDescriptionInitiated ByImpacted PopulationEnded by
Zero Tolerance PolicyThe zero-tolerance policy required each U.S. Attorney’s Office (USAO) along the Southwest border to prosecute all U.S. Department of Homeland Security (DHS) referrals for illegal entry violations “to the extent practicable, and in consultation with DHS.”Introduced by the Trump administration in May 2018.This policy applied to individuals crossing the Southwest border illegally. Family unit adults were referred to the Southwest Border USAOs for prosecution resulting in family separations until the program ended.Terminated under the Trump administration in June 2018.
Migrant Protection Protocols (MPP, also called Remain in Mexico)Under the MPP, individuals arriving in or entering the U.S. from Mexico illegally or without proper documentation may be returned to Mexico for the duration of their immigration proceedings.Implemented by DHS in January 2019 under the Trump administration.Individuals coming into the U.S. illegally or without proper documentation from Mexico.Initially terminated by DHS memo in June 2021, ordered reinstated by federal court in August 2021. DHS terminated again in October 2021, reinstated by appeals court in late 2021. The Supreme Court, on appeal in June 2022, remanded the case. In August 2022, the Biden administration ended the program. A district court again stayed the termination memo in December 2022, but did not order the administration to restart the program. It remains in litigation but has not been resumed.
Third Country Asylum RuleThis policy deemed immigrants who failed to apply for protection in a third country outside of the person's citizenship, nationality, or last lawful habitual residence, en route to the U.S. ineligible for asylum.Implemented under the Trump administration in July 2019.Immigrants who attempt to enter or have entered through the Southern land border and failed to apply for protection in another country.Terminated in June 2020 by a federal court order.
Prompt Asylum Claim Review (PACR)This program was started to more quickly process and remove migrants who did not qualify for asylum. Border Patrol agents completed initial assessments of those migrants and transferred them to a temporary, modular Central Processing Center (CPC) for United States Citizenship and Immigration Services (USCIS) to conduct rapid credible fear screenings.Implemented first in El Paso, TX, by DHS in October 2019 under the Trump administration. Covered the Southwest border by February 2020.Applied to non-Mexican single adults and family units apprehended by Border Patrol who were subject to the Third Country Asylum Rule in place at the time.Terminated by the Biden administration in February 2021.
Humanitarian Asylum Review Process (HARP)This program is similar to PACR. However, the Office of Federal Operations (OFO) handled the initial processing of those subject to the pilot program at the port of entry, transferring them to Border Patrol’s CPC facility to continue the asylum process. It was meant to expedite credible fear interviews for those placed into expedited removal proceedings but who had expressed a fear of return.Implemented by DHS in October 2019 under the Trump administration.Applied to Mexican single adults and family units apprehended by Border Patrol primarily at ports of entry beginning at the Paso del Norte port of entry in El Paso, Texas.Terminated in February 2021 under the Biden administration.
Title 42This policy allowed U.S. officials to turn away migrants on the grounds of preventing the spread of COVID-19.Enacted under the Trump administration in March 2020.Migrants who came to the U.S.-Mexico border. Depending on various agreements with Mexico, migrants of some nationalities were returned to Mexico while others were returned to their home countries.Terminated in May 2023 under the Biden administration.
Family Expedited Removal Management (FERM)This process places the head of households for family units on Alternatives to Detention (ATD) consisting of a home curfew with GPS monitoring by ankle bracelet or the SmartLINK phone app. Families are required to attend check-ins with U.S. Immigration and Customs Enforcement’s (ICE) and contractors implementing the monitoring program. Families in this program are subject to expedited asylum interviews.Implemented by ICE Enforcement and Removal Operations (ERO) under the Biden administration in May 2023.This process applies to certain family units that are apprehended at the Southwest border who are processed for expedited removal and show an intention to apply for asylum or express a fear of persecution or torture.Active.
Circumvention of Lawful Pathways RuleThis policy creates rebuttable presumptions against eligibility for asylum seekers who didn’t apply for protection in other nations they transited on their way to the U.S., unless they came through a prescheduled appointment at a port of entry or meet a narrow set of exceptions.Implemented under the Biden administration in May 2023.Immigrants who attempt to enter or have entered through the Southern land border either at a port of entry or between ports of entry.The rule is still in place as of December 2023.

The court that ruled against the Trump era Third Country Asylum rule issued an order against the Biden rule in May 2023, but stayed its decision pending appeal.
Parole Process for Cubans, Haitians, Nicaraguans, and Venezuelans (CHNV)This program allows certain people from four countries who have a sponsor in the U.S. and pass a background check to come to the U.S. for a period of two years to live and work lawfully.Initially implemented under the Biden administration for Venezuelans in October 2022 and expanded to Cubans, Haitians, Nicaraguans, and Venezuelans in January 2023.Immigrants who are nationals of Cuba, Haiti, Nicaragua, Venezuela or are the immediate relative of a national of one of these countries applying for the program. Has a supporter in the U.S. who has filed a Declaration of Financial Support (Form I-134A) on behalf of the applicant and been approved by USCIS. Must have a passport, pay for their own flight to the U.S., be vaccinated for measles, polio, and COVID-19, and pass all background checks.Active.

Apprehensions Levels and Policy Changes

The chart below displays how or whether the policies may have influenced border apprehension numbers based on their start and end dates. Border apprehension numbers refer to the count of individuals detained at the Southwest land border by U.S. Border Patrol and excludes those encountered at legal crossings. While the graph may indicate some correlations, it should not be interpreted as determinative of causation.

Southern Border Apprehensions and Policy Changes (2014-present)

Graphics by Alexander Varisco

Overall, the data highlights the absence of a consistent immigration policy at the border. It is challenging to attribute a surge or decline in apprehension numbers to the implementation of a specific policy when multiple policies are in play at any given time, and so many policies and other factors impact migration patterns.

Additionally, different border areas may have had different policies in place due to local conditions. Some programs apply only to certain nationalities, such as the country-specific parole programs or the PACR and HARP programs, or to specific demographics, such as the FERM program. Since we only map overall apprehensions in this blog, a more granular look at how these programs may have influenced different demographics might show different responses.

Extraneous factors also contribute to border apprehension numbers. For instance, Title 42 was implemented to address the COVID-19 pandemic alongside general travel restrictions within and between the United States, Canada, Mexico, and other countries in the hemisphere that could have also affected border encounters. Throughout the period, countries may have lifted or applied visa or other travel restrictions to certain nationalities that could limit movement through the hemisphere. It should also be noted that while other policies during the Trump administration technically remained in place after Title 42 began, for all practical purposes they were not used in favor of the Title 42 expulsions until they were formally ended by the Biden administration. Finally, unintended outcomes of various policies may also affect the apprehension numbers. It has been widely acknowledged migrants to Mexico during Title 42 resulted in higher numbers of repeated crossing attempts which inflated apprehension data during its tenure.


In recent years, apprehensions at the border have become an increasingly politicized issue, with partisans touting the effectiveness of the policies of presidents of their party. Yet the data shows the picture is far from clear-cut. The inconsistent nature of the policies in place (in part due to litigation and court decisions) and overlap in implementation timelines make it difficult to clearly understand the effects of individual policies. The data also does not reflect the continued changes in the demographics and nationalities of those arriving, nor the “push” factors that have sent them to the border. However, continued fluctuation in numbers of arrivals at the border is expected if there is no consistent immigration policy to address the ongoing migration crisis.

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