Trump’s Mexican Border Wall

This Review was written by Zachary Grassby on the effectiveness of the US-Mexican Border Wall.


In 2016, Donald Trump stormed into the White House, largely due to one defining campaign slogan: “Build that wall!” The idea of a 20ft high concrete wall separating the US from Mexico rallied Republican support and the promise that Mexico would pay for its reinforced voters’ hopes and expectations. Yet Mexico and the US are in many ways socially, culturally and strategically co-dependent, sharing a 2000-mile border that is relevant to millions of workers and important trade networks. This fact sheet looks at the proposed border wall and assesses its effectiveness from an economic, environmental and political perspective.

Historically, Mexicans crossed theUS border to work as farm labourers, doing low income jobs with anti-social hours which were important to the region’s economic growth. The attractions were clear.The significant differences in economic, social and lifestyle factors proved a powerful draw for Mexicans looking to improve their lives whilst the US economy benefited from access to flexible low-cost labour.

Figure 1: Comparison of characteristics for USA and Mexico

In the early 1980s, an economic recession halted global growth. Unemployment in southern states of the US rose and resentment against immigrants started to build as Americans now wanted jobs occupied by Mexicans. In 1990, President Bush ordered the construction of a barrier stretching 14 miles along the San Diego-Tijuana border. Then President Clinton added three more, in California, Texas and Arizona, as well as increasing reinforcements to existing barriers. However, this reduced migration flows by only 0.8%. It also subsequently became clear that immigrants were no longer returning home and both legal and illegal migrants were becoming a bigger feature of the long-term make-up of the US workforce.

Figure 2: Existing border security pre 2017

In addition, small businesses and agricultural pursuits in the South had come to rely heavily on undocumented migrants who worked for as little as $5 per hour. Without this, they would be in danger of collapsing. The US’s southern border with Mexico runs for nearly 2,000 miles over diverse terrainandthrough varied population densities. The Department of Homeland Security (DHS) Customs and Border Protection (CBP) is responsible for border security, surveillance and the deployment of border patrol agents to apprehend the unlawful entry of people and contraband including unauthorized migrants, terrorists, firearms, and narcotics.

Before Trump took office, there were 654 miles of barrier along the southern border – made up of 354 miles of barriers to stop pedestrians and 300 miles of anti-vehicle fencing.

Migration is once again a major issue:

•In 1970 migrants made up 4.7% of the total US population – today this figure is 15% representing a total of 44.7m which is at an all-time high;

•Of these, an estimated 10.5m are unauthorised immigrants; and

•10,000 migrants per week attempt to cross the southern border of the US (1/3 are detained and sent back but will attempt to cross the border on average twice a year).

Although counting arrests does not necessarily yield a reliable estimate of the number of border-crossers who evade detection, the Pew Hispanic Centre estimates that the total who do make it through had fallen by 2017, to less than a third of its maximum level.

The causes of this decline are open to debate. Now, nearly a decade after the original wall was built, arrests have dwindled almost everywhere — both in areas separated from Mexico by existing fences and in those where the Rio Grande forms a natural obstacle. Whether the wall was responsible for this trend is contested: the end of Americaʹs housing boom, which created large numbers of construction jobs filled by Mexican immigrants, probably also played an important role. The result was though, that total unauthorised migration had actually been falling until 2019.

Figure 7:

The recent escalation in detentions has caused the topic of migration to hit the news once again-xenophobia, nationalism and anti-immigrant sentiment have continued to grow in the US just as they have elsewhere across the globe. Migration isn’t the only issue. In recent years, the border has been a major battlefront in the war against drugs with border access said to account for 90% of all narcotics entering the US annually.

Figure 8:

Trump’s “Big, Beautiful Wall”

Trump’s “Big, beautiful wall”In the run-up to his election victory, Trump promised to build a wall along the border’s entire 2,000-mile length. He signed two executive orders on the 25th January 2017 which enacted the following:

•Mandated the immediate construction of a border wall;

•Prioritised the hiring of 5000 border officers (tripling the figure at the time) and extending their powers; and

•Commenced the process to raise initial funding of $5.7bn.

Although Trump met with some initial success, he struggled to get his proposals fully funded–by 2020 $13.3bn of requested funding through the Appropriations process only yielded $3.1bn of investment due to political resistance.

“I will … secure the southern border of the United States through the immediate construction of a physical wall on the southern border, monitored and supported by adequate personal so as to prevent illegal immigration, drug and human trafficking, and acts of terrorism”

In February 2019, his frustrations led him to declare the southern border a National Emergency and sought to re-designate Department of Defence funding to finance the barrier. He requested $5bn in border barrier funding for FY20, to support the construction of a further 206 miles of border wall system. The House Appropriations Committee responded by providing no funding in its FY20 bill for border barriers and proposed rescinding $601m from funding appropriated for border barriers in FY19.

Better alternatives?

As a result, progress has been slow. Overall, $10bn has been secured since January 2017 to construct approximately 509 miles of “new border wall system”, according to US Customs and Border Protection (CBP). A total of 57 miles of replacement barrier and nine miles of new secondary barrier have been constructed -a total of 66 miles. However, no “new wall” – any extension to existing structures – had by the end of 2019 been completed. Also, the final proposed cost of Trump’s wall has become a political and economic football. Trump’s initial estimate of $8bn is now out-of-date and most observers estimated substantially greater funding requirement, with most people citing a need for $20bn -$40bn – and the prospect of having the Mexican government pay for it was unsurprisingly firmly rebutted. Other proposals have included:

•Applying an import tariff of 20% to all Mexican imports; Taxing migrants’ remittances; and

•Publicly strong-arming US manufacturers (such as Ford and Carrier) torelocate production to the US.

Whilst progress on the wall has been slow, Trump has been more successful implementing othermigration initiatives, including:

•Restricting legal immigration; reducing acceptance of asylum seekers and refugees; terminating welfare benefits for unauthorised immigrants; deporting previously protected child immigrants; restricting travel and visa acceptances from certain countries; Imposing increased costs for migrant entry applications; increasing threefold the number of face-to-face interviews for employment visa and green card applicants; and Raising the baronH-1B visas for even highly qualified technical workers.

The results here have been quick, material and achieved at low cost. The number of immigrant visas issued in 2016 was 617,752-three years later the number stood at 462,422, a 25% decline. However, as mentioned earlier, these declines have been more than offset by the recent resurgence in illegal migration.

A smart investment?

A recent review by three economists from Stanford University and Dartmouth College concluded that the proposed spending would have a poor return on investment-for every 19 cents the government spent building the wall, the economy has declined,and low-income U.S. workers have gained only a cent of extra income. The economists found; expanding the wall would only reduce the number of Mexican workers in the US by 144,000 — about 1 percent. The incomes of low-skilled workers without college degrees would increase by only 58 cents a year, far less than the cost per American ($15) to build the wall–equivalent to a 30-year payback. Furthermore, incomes of higher-skilled workers would fall by $7.60. On top of the cost to build the wall, the economy would lose more than $4bn a year, meaning the US would lose nearly $30,000 in economic output for each Mexican migrant the wall stops.

“Our research shows that building a wall was an ineffective way of reducing migration. It was expensive to build and its harmed US workers”

The environmental impact?

The border wall also has several worrying environmental impacts: spoiling urban and rural landscapes; exacerbating flood plains causing millions of dollars in reparations; endangering rare wildlife and plants including separating 346 wildlife species; and disrupting wildlife refuges and national parks – the wall cuts through seven wildlife conservation areas in Texas alone. Construction of the wall thus far has required exemption from the usual environmental oversight laws as it is in direct violation of 30 federal regulations.


The governor of Arizona and president of Homeland Security under President Obama, famously declared “Show me a 50-foot wall and I’ll show you a 51-foot ladder.” The wall has proven ineffective as a valve on migration as the beneficial effects of tighter regulation have been more than offset by an increase in the level of illegal migration. As an investment, the economics don’t really add up, and from an environmental perspective, it’s a white elephant. So why build it? Trump’s heartland political support rallies to the dog-whistle of high profile, aggressive, action-oriented policies. Perhaps the wall has done enough for him to be re-elected in November.

(Featured Image: © Tomas Castelazo)