Building a Wall Along the Southern U.S. Border: Impacts and Unanswered Questions

In 1911, the first “wall” erected between the United States and Mexico was a chainlink fence meant to stop cows from crossing and spreading tick disease. Since then, U.S. presidents and various legislation have revisited the idea of creating a barrier along the nearly 2,000-mile stretch of border between the two countries to prevent people from crossing without permission.

Constructing physical barriers at the U.S. southern border touches on a variety of issues important to people across the political spectrum. Remarkably, the notion of building a wall has elicited both bipartisan support and opposition.

Beginning with Democratic President Clinton and continuing through Republican President Trump, the last five presidents have proceeded with barrier building in an attempt to manage immigration issues. Meanwhile, diverse groups of people have opposed the idea. For instance, environmentalists in New Mexico may oppose a barrier due to the harm it poses to wildlife, aligning with a family of Texas ranchers who oppose the government’s plans to build on their private property.

Despite opposition or support for a border wall, it is clear that efforts to build a continuous wall are moving forward. As the U.S. continues to wrestle with the complexities involved in attempting to physically separate itself along this vast stretch of land, this article explores a few examples from six categories of impact and highlights unanswered questions.

Impact on immigration

Humanitarian concerns

One issue worth serious consideration is how a continuous barrier across the border would affect migrants. Hundreds of people die every year attempting to go over, around, and through barriers across the U.S.-Mexico border region. In 2019, a wall height increase along a section of border between Mexico and San Diego was associated with a sharp increase in traumatic injuries and deaths as migrants continued to attempt to scale the “unclimbable” wall.

Border wall enforcement mechanisms rooted in a strategy known as “prevention through deterrence” seek to seal off urban entry points and redirect migrants into more remote terrain with the objective of discouraging unauthorized entry into the U.S. However, human rights watch groups, advocacy organizations, former Border Patrol officials, and migrants themselves have raised concerns that these policies expose migrants to dehydration, injury, heat stroke, exhaustion, hypothermia, and exploitation by criminal organizations. Researchers argue that while such measures may succeed in making unauthorized crossing more difficult, they also contribute to making crossing more deadly, with recorded fatalities likely understating the actual number of deaths in the borderlands.

As areas of the U.S.-Mexico border have become more heavily guarded, many migrants have increasingly attempted to cross through more remote and dangerous areas in order to avoid apprehension and preserve the possibility of petitioning for asylum. During the Biden administration’s use of the CBP One app to manage appointment requests at ports of entry (now known as CBP Home for self-deportation purposes), lengthy wait times in Mexico contributed to perceptions among some migrants that dangerous crossings offered a faster means of entering the U.S. In Texas, Operation Lone Star, which utilizes buoys, fences, shipping containers, and concertina wire, has also been criticized for redirecting migrant crossings into more hazardous areas and complicating rescue efforts by U.S. Customs and Border Protection personnel on both land and water.

Methods to secure the border

Besides a physical wall, a variety of other methods are employed to deter people from crossing the border. Devices include, but are not limited to, trained dogs, tower surveillance, aircraft, and cargo scanners. Each of these comes with its own set of costs, risks, and benefits, but none offers a comprehensive solution. Despite support for the ongoing construction of a border wall largely falling along partisan lines, many members of the GOP and former members of President Trump’s administration agree that a border wall is too simple and misleading an answer for a complicated issue.

A paper on MWEG’s principle of ethical government 3(d) states: “[t]he lack of good policy creates unfair systems that potentially expose people to abuse and harm; this gap also limits the ability of both private citizens and the government to effectively help them.”

Key unanswered question: Are barriers, including walls, working to deter people from illegally entering the U.S.?

Impact on the environment

The desert southwest is teeming with an enormous diversity of plants and wildlife. Environmentalists, agencies, residents, and more share concerns about the potential environmental impact of an expansive physical border on the ecosystems of this region. Construction of a wall requires the clearing of vegetation, the destruction of topsoil, and the building of support roads, all of which have resulted in erosion and flooding. It could alter the flow patterns and watershed of the Rio Grande.

Research done in areas where a physical wall exists shows that barriers sever wildlife migration routes. In one study of an area along the southwest border where a wall already exists, only 9% of wildlife interactions with the border wall led to successful crossings. Animals such as the Sonoran pronghorn and the already endangered Mexican wolf are prevented from paths to food and water and from migration for mating. This could increase extinction rates, which would impact the entire ecosystem, including the 15 million humans who live near both sides of the border.

MWEG’s principle of ethical government 2(f) states: “Governments and members of society have an obligation to exercise responsible stewardship of the earth, thereby protecting not only the wellbeing of their citizens, but also that of both future generations and other citizens of the planet.”

Key unanswered question: Are the environmental impacts of a physical barrier irreparable?

Impact on land use

As tractors roll through towns, public and private land users await construction of the wall slated to begin June 1, 2026, along parts of the border near Big Bend National Park and Big Bend Ranch State Park in Texas. A 30-foot steel wall is planned through the area and surrounding private properties; it will cut off public access to parts of the Rio Grande. The wall expansion project already bulldozed an ancient Native American archeological site in Arizona.

Destruction or disruption of archeological sites isn’t the only impact, though; privately owned homes, views and trails in a national park, and access to water are also at risk. A self-employed photographer in the region lamented, “I care deeply about this region. I think that it is a part of Texas heritage, and the concept of needing this or doing this is just so un-Texan.”

With its 62 miles of land along the southwest Arizona border, the Tohono O'odham Nation is particularly vulnerable to direct impact from the construction of a wall — despite their successful efforts at tracking drug smugglers and helping to secure the border. Tribal leaders say that building a continuous wall would not only trample their land rights, it would also infringe on their sometimes daily crossings to visit family or gravesites of ancestors.

Key unanswered question: Does sufficient data exist to justify a broad expansion of a wall between the U.S. and Mexico that would deter unauthorized border crossings? 

Impact on the legal system

To complete a physical wall across the entire border between Mexico and the U.S., the federal government (as of 2018) would need to initiate the seizure of 5,000 parcels of land. The government typically has a right to seize private land as long as it compensates the owners. After the 2006 Secure Fence Act, government land seizures for a border wall began in Texas. The government brought 300 eminent domain cases against private property owners, causing a flood of litigation. The legal process can take years if homeowners dispute the compensation amount. Many of these cases had not been resolved a decade later, and it is unclear how many seizures would still be required. One expert added, “We are looking at years, decades, of court cases."

Key unanswered question: Given the existing legal challenges, is it appropriate and feasible for the U.S. to seize private land from individual landowners?

Impact on the economy 

The full economic impact of a completed wall is difficult to imagine with so much yet unknown. The costs of building a wall of the proposed size are estimated at $17 million per mile with funding approval that passed as part of the One Big Beautiful Bill Act in 2025. The expenses extend beyond the structure of the new “Smart Wall” itself, however. Namely, since much of the border lies hundreds of miles away from the nearest U.S. city, construction would necessitate creating access roads to safely transport equipment and laborers and patrol once finished. Part of the region that enjoys a healthy tourism economy would also be sacrificed to create areas off limits to the public.

Key unanswered question: Would the costs of building a wall be better applied to staffing for immigration applications (e.g., more judges, tackling the backlog, etc.)? 

Ethical considerations

MWEG’s principle of ethical government 1(b) states: “Government officials and institutions should be honest and transparent, insofar as possible without harming national security and individual rights (see D&C 123:13; Alma 37:25).”

Lack of transparency

Plans to build the border wall have been mired by a lack of honesty and transparency from the U.S. government. U.S. Customs and Border Protection (CBP), the federal agency responsible for the project, has been elusive about the exact location of the wall in certain areas, even rescinding initial promises that it would not encroach on national park lands. A map that illustrated the wall going through Big Bend National Park has been removed from the agency’s website.

Disregard of federal regulations

The justification for disregarding previous federal regulations in order to build a border wall comes from a series of executive orders written by the second Trump administration citing an “invasion” and “a national emergency.” Advocates say there is no such emergency, and many of the orders continue in litigation over this controversy. Marfa Public Radio reported that some of the “federal regulations to be waived are the National Environmental Policy Act, the Endangered Species Act, the Clean Water Act, and a variety of wildlife and historic resources protection laws.”

Political scandals

The wall-building project is also embroiled in political scandals. For example, one of the contractors is a construction company with a history of environmental violations and legal and political problems of their own. And the CBP itself is being sued for withholding public records. 

Key unanswered question: Should affected communities and American taxpayers expect more transparency in the building of multi-billion dollar federal projects?

The U.S. has a constitutional right to secure and defend its border. However, even as a wall is being constructed, Americans are still deeply divided about the necessity of a physical barrier. Important questions must be addressed regarding the humanitarian impacts, the negative environmental consequences, and the use of taxpayer funds.

This article was written by Sherilyn Stevenson, lead researcher/writer, with Paulette Stauffer Henriod, environmental specialist, and Alexa Alvarado and Nori Gomez, immigration specialists at Mormon Women for Ethical Government.