·  U.S. Customs and Border Protection, along with a few agencies, regulates trade and travel at U.S. ports of entry and across the country’s borders.

·  While President Biden reversed some Trump-era policies, which tightened security at the U.S.-Mexico border, he kept a troop presence there and restricted asylum access in response to a record number of migrant arrivals.

·  Since returning to office, Trump has once again made securing the southern border a national security priority, including by deploying thousands of troops there.

Safeguarding the southern U.S. border, primarily the responsibility of the Department of Homeland Security (DHS), remains a contentious and evolving issue as an increasing number of migrants from Asia, Central America, and elsewhere seek to enter the United States via Mexico. During his first term, President Donald Trump clashed with Democratic lawmakers over border wall funding, leading to a government shutdown, a presidential emergency declaration, and the deployment of thousands of National Guard and active-duty troops to the border.

President Joe Biden initially reversed many Trump-era policies—halting construction of the border wall, easing some restrictions on asylum seekers, and pursuing regional diplomacy to target the root causes of irregular migration. But ongoing migrant surges overwhelmed the U.S. immigration system and tested federal enforcement capabilities, prompting the administration to resume some construction of the border wall and tighten asylum access.

In his second term, Trump has again framed the border as a national security priority, ramping up enforcement measures there. His administration has declared a renewed national emergency, expanded military deployments, and designated parts of the border as federally controlled National Defense Areas.

What’s Happening at the Southern U.S. Border?
The U.S. immigration system has come under increasing strain in the past decade. After the number of migrant arrivals plunged in 2020 due to the COVID-19 pandemic—falling to less than five hundred thousand—illegal border crossings soared post-pandemic before receding once again. In fiscal year 2024 (FY 2024), U.S. immigration authorities encountered more than 2.1 million people at the U.S.-Mexico border, only slightly less than the record high of close to 2.5 million the previous year. Nearly a fifth of all migrants in 2024 came from the so-called Northern Triangle countries of El Salvador, Guatemala, and Honduras. Other major countries of origin included Colombia, Cuba, Mexico, and Venezuela.