Resources on Immigration : Law and Policy

This 1798 law allows the president to detain, relocate, or deport noncitizens who are considered an enemy of the United States during a time of war. The law is part of the four-part Alien and Sedition Acts of 1798, which together sought to restrict speech and immigration in the United States. Trump says he will use the act to bypass normal due process in his proposed deportations of members of criminal gangs and drug cartels.

Section 1 of the Fourteenth Amendment of the U.S. Constitution, adopted in 1868, grants citizenship to anyone born in the United States. Trump has previously said that he will sign an executive order to ensure that “the future children of illegal aliens will not receive automatic U.S. citizenship,” though legal scholars say that would require changing the Constitution.

CBP is the federal law enforcement agency within the Department of Homeland Security (DHS) responsible for enforcement at U.S. borders, as well as at and between official ports of entry, such as airports and seaports. Trump frames border enforcement as a national security priority. For his second term, he has called for adding some ten thousand border patrol agents and completing the border wall.

President Barack Obama created DACA through an executive order in 2012, establishing a program that provides temporary deportation relief to undocumented immigrants who came to the United States as children. Trump suspended DACA in 2017, calling it unconstitutional and arguing that Congress should legislate a more permanent solution. After a series of court battles, the Supreme Court ruled in 2020 that the Trump administration didn’t have adequate justification for ending the program, though it is no longer accepting new applicants. Since its creation, DACA has benefited more than 800,000 immigrants; more than 535,000 DACA recipients, commonly known as Dreamers, live in the United States. The future of DACA remains uncertain.

The FSA is a 1997 court settlement that outlines basic standards of care for both accompanied and unaccompanied minors, such as access to food and water, emergency medical services, and bathroom facilities. During Trump’s first term, authorities separated more than 5,500 families, ostensibly to protect children, including from traffickers and other adults who could harm them. The administration tried to override Flores settlement regulations and allow DHS to indefinitely detain families, which it argued would end the need to separate children from guardians; a federal judge blocked those efforts in 2019. President Joe Biden also moved to end the Flores settlement and create new policies to address family detention at the southern U.S. border.

Several foreign worker visas allow U.S. employers to hire immigrants for temporary jobs. Among the most popular are the H1B (requiring specialized knowledge), H2A (agricultural workers), H2B (seasonal workers in nonagricultural fields), and H4 (spouses or unmarried children of H-visa holders) programs. The U.S. government issued close to nine hundred thousand visas [PDF] for these four programs combined in fiscal year 2023. Trump promised to reform such worker programs in line with his Buy American and Hire American agenda, including by tightening eligibility standards, though his proposals stalled in Congress, and his administration halted most foreign worker visa programs during the COVID-19 pandemic. Meanwhile, Trump has advocated for boosting high-skilled immigration, promising to give a green card to foreign-born college graduates.

Humanitarian parole temporarily allows noncitizens to reside in the United States based on what the government considers “urgent humanitarian reasons” or “significant public benefit.” Presidential administrations have used parole powers for more than seven decades. Biden has repeatedly used humanitarian parole, including for Afghan nationals following the U.S. withdrawal from Afghanistan in 2021 and Ukrainians in the wake of Russia’s 2022 invasion. His administration also established a new parole program specifically for nationals of Cuba, Haiti, Nicaragua, and Venezuela (CHNV) in response to heightened instability in those countries. Trump has indicated he wants to end the CHNV program and has said he will revoke the humanitarian parole grants from migrants already in the United States.

ICE, also within DHS, is responsible for internal immigration enforcement, including apprehending and deporting undocumented immigrants. (An estimated eleven million plus undocumented immigrants currently live in the United States.) Such removals lagged during Trump’s first term, in part because of limits on detention space, backlogs in immigration courts, and pushback from so-called sanctuary cities—jurisdictions that have put in place policies to limit cooperation with or involvement in federal immigration enforcement efforts. Trump has promised to implement the country’s largest-ever deportation operation modeled after President Dwight D. Eisenhower’s mass deportations under the 1954 Operation Wetback.

This 1807 law empowers the president to deploy the U.S. military and federalized National Guard troops for civilian law enforcement purposes in the event of rebellion or other civil disorder. U.S. presidents have invoked the act some thirty times, most recently President George H. W. Bush in response to the 1992 Los Angeles riots. Trump has said he will invoke the act to use federal troops to apprehend migrants at the U.S.-Mexico border. The Insurrection Act is the main exception to the 1878 Posse Comitatus Act, a federal law that forbids the U.S. military from engaging in civilian law enforcement.

Also known as green card holders, LPRs are noncitizens who are legally allowed to live in the United States permanently; they enjoy a host of benefits including the right to live and work anywhere in the country, own property, attend school, and apply for citizenship after they meet certain eligibility requirements. Roughly one million green cards are issued each year. During Trump’s first term, he framed the Diversity Immigrant Visa (DV) program, sometimes called the green card lottery—a program administered by the State Department that provides visas to people from countries with low levels of emigration to the United States—as a national security threat and called for Congress to end it. Biden put forward an ultimately unsuccessful immigration proposal to increase DV slots from fifty-five thousand to eighty thousand.

Also known as “Remain in Mexico,” Trump’s MPP policy required non-Mexican asylum seekers to wait in Mexico while their cases were processed in U.S. immigration courts. The policy was meant to stem what the administration considered an alarming rise in asylum seekers at the southern U.S. border, which it said was overwhelming the U.S. asylum system. Critics said the program was inhumane and a reversal of a long-standing practice, given that U.S. law generally grants asylum seekers who arrive at the border the right to remain in the country while their application is pending. Biden officially terminated the program in 2022 after a series of legal battles; Trump has said he will restore it.

The Trump administration sought arrangements with several Latin American countries to allow U.S. authorities to send asylum seekers who traveled through those countries on their way to the U.S. border back there. Under the agreements, some migrants’ asylum claims would not be heard in the United States if they had not previously applied in the first safe country they reached. Only the agreement with Guatemala was implemented, though Guatemala City terminated it in 2021.

TPS is a legal tool similar to humanitarian parole that grants migrants from countries the U.S. government considers unsafe due to conflict, natural disasters, or other extraordinary conditions the right to live and work in the United States for up to eighteen months, which can be renewed indefinitely. TPS holders are not considered lawful permanent residents or U.S. citizens, though many have lived in the country for decades. As of March 2024, more than 863,000 TPS holders [PDF] live in the United States. Trump sought to end TPS protections for immigrants from several countries in his first term, but his efforts were slowed by legal challenges. He has indicated he will again try to roll back TPS designations for some groups of immigrants, including those from Haiti.

Part of the Public Health Service Act of 1944, this statute allows the director of the Centers for Disease Control and Prevention—with approval from the president—to turn away migrants to prevent the possible entry of communicable diseases. Trump invoked Title 42 amid the COVID-19 pandemic in 2020, allowing the government to quickly expel millions of migrants trying to cross the southern U.S. border. Biden lifted Title 42 in 2023; Trump has said he would revive it. With Title 42 lifted, immigration enforcement returns to Title 8, the section of the 1980 asylum law that allows CBP officers to process and potentially remove migrants who entered the country without authorization.