International Reports

Walls Against Migration?

by Victoria Rietig, Christian Bilfinger

About Perceived Truth in the U.S. Migration Debate and the Effectiveness of Border Protection Measures

Donald Trump’s plan to build a wall along the U.S.-Mexico border shines a spotlight on the issue of border protection. This article investigates how effectively walls and border control measures reduce unwanted migration flows, compared to efforts to fight root causes, and analyses as to why new migration trends in the United States and Mexico are being neglected in the U.S. debate.
The U.S. Capitol, home of the U.S. Congress, photographed behind a chain fence in Washington, D.C.
The U.S. Capitol, home of the U.S. Congress, photographed behind a chain fence in Washington, D.C.

1. Introduction

“They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people.” These are the words new U.S. President Donald Trump used in the election campaign to warn against allegedly unchecked illegal immigration from Mexico. This warning is surprising insofar as illegal migration from Mexico to the United States is at a historic low, and for more than ten years, more Mexicans have been moving from the United States to Mexico than vice versa.

The solution proposed by Donald Trump appears no less bizarre: “I would build a great wall, and nobody builds walls better than me, believe me (…) I will build a great, great wall on our southern border. And I will have Mexico pay for that wall.” Long stretches of the 3,000 kilometers U.S.-Mexican border are already protected by border fortifications which have been erected gradually since the 1990s – but migration experts view their effects critically. Meanwhile, leading Mexican politicians agree that Mexico will have no part in its neighbour’s wall-building endeavour.

Trump’s quotes reflect a fundamental trend: the migration discourse in the United States is increasingly divorced from facts. This article analyses this discourse and offers responses to three questions: First, how has the migration dynamic between the U.S. and Mexico changed in recent years? What do the statistics say? Second, why are basic migration facts ignored in the political debate in the United States? What reasons explain this phenomenon? Third, how sensible are solutions currently under discussion in the U.S. (and increasingly also in Germany)? How effective are walls and border protection in reducing unwanted migration compared with efforts to fight root causes? This article aims to dissect the U.S. debate to highlight parallels with Europe and lessons for Germany.

2. New Migration Dynamics – Fewer Mexicans, More Central Americans

The engrained narrative of Mexican immigrants who are entering the United States illegally and whose number rises continuously has been outdated for some time.

Mexican Migration: A Downward Trend

Illegal migration from Mexico is currently at a historic low. While over a million undocumented Mexicans were arrested at the border in 2005, it was fewer than 200,000 ten years later. At the same time, an increasing number of Mexicans return home from the United States. Net migration between the U.S. and Mexico, i.e. the difference of immigration and emigration levels, has been negative for a number of years now. Between 2009 and 2014, one million Mexicans left, while only some 870,000 arrived. Since 2013, China and India have been the main countries of origin of new U.S. immigrants, while Mexico only ranks third. According to data from the Census Bureau, around 125,000 Mexicans immigrated into the U.S. in 2013, compared to 147,000 Chinese and 129,000 Indians.

Reasons for the decline of Mexican immigration are manifold. The 2008 recession in the U.S. and simultaneous improvements in Mexico’s job market play as much a role for returnees as the desire to reunite with their families. The falling birth rate and aging population in Mexico also reduces the number of potential new emigrants. And increased U.S. border protection and rising deportations further lowers the motivation to migrate.

Despite reduced migrant flows in the last few years, the Mexican migrant stock in the U.S. continues to be large. The Mexican diaspora has remained constant at close to twelve million for a number of years, accounting for almost a third of all foreign-born in the United States. Around half of Mexican immigrants – some six million people – live in the U.S. in an irregular status.

These impressive statistics are the result of decades of continuous legal and illegal immigration. Starting in 1942, many Mexicans came to the U.S. legally on temporary work visas via the so-called Bracero Program. When the program came to an end in the mid-1960s, many Mexican guest workers maintained the close relationships they had established with their U.S. employers and continued to travel to the U.S. to work, albeit now illegally. Legal migration from Mexico also increased as a revision of U.S. migration legislation in 1965 introduced generous rules on family unification. While fewer than one million Mexicans lived in the U.S. in the 1970s, their number had more than doubled to 2.3 million by 1980 and then increased exponentially, reaching 11.7 million in 2010, where it has stabilised with modest fluctuations ever since.

Migration from Central America: An Upward Trend

While the number of Mexicans coming to the U.S. is falling, the number of Central American migrants is rising steadily. Hundreds of thousands of people from El Salvador, Guatemala and Honduras, the “Northern Triangle” of Central America, set out for the U.S. every year and cross Mexico as transit migrants.

Note: Customs and Border Protection (CBP) classifies apprehensions as “Mexicans” and “Other than Mexicans (OTMs)”, whereas the great majority of the OTM migrants originate from the Northern Triangle. Source: Own Illustration based on U.S. Customs and Border Protection (CBP) 2016, U.S. Border Patrol Apprehensions From Mexico and Other Than Mexico (FY 2000-FY 2016), pp. 2–3, in: (28 Feb 2017).

As figure 1 illustrates, particularly illegal migration from Central America has increased. While some 110,000 Central American migrants attempted to cross into the U.S. illegally in 2006, that number had more than doubled by 2016. In conjunction with the strong decline in illegal migration by Mexicans, this means that the proportion of Central Americans among those apprehended soared in this period, from tento 54 per cent. The fact that today more Central Americans attempt to cross the border than Mexicans is all the more impressive when you consider that these three countries alone have a combined population of around 30 million – just a quarter of Mexico’s population.

Northward migration from the Northern Triangle also goes back a long way. In the 1970s, many Central Americans were drawn to the U.S. from their home countries, partly due to civil war and political unrest at home, partly to find work in the U.S., or to join members of their family living there. The Central American diaspora in the U.S. consequently expanded from fewer than 200,000 in 1980 to almost three million in 2015 (cf. fig. 2).

Source: Own illustration based on Migration Policy Institute 2016: Largest U.S. Immigrant Groups over Time, 1960-Present, in: (24 Mar 2017).

Today, the region is still fragile and mired in a multitude of problems. People suffer from extreme levels of violence, with murder rates between 30 and 75 murders per 100,000 inhabitants (in Germany the rate is below 1). Poverty and unemployment are wide-spread and a quarter of all young people are so-called ninis, who are neither in work nor in education. Massive corruption exacerbates increasing social inequalities, and weak institutions are eroded further by the overwhelming influence of gangs.

Central American migration to the U.S. made headlines especially in 2014, when over 68,000 unaccompanied minors, travelling without a parent or guardian, were apprehended at the border. Three quarters of these children came from El Salvador, Guatemala and Honduras. Compared to the previous year 2013, their number had jumped from some 20,000 to 50,000, while the number of Mexican children remained relatively stable (cf. fig. 3).

Source: Own illustration based on CBP 2017: U.S. Border Patrol Southwest Border Apprehensions by Sector, 8 Mar 2017, in: (24 Mar 2017).

President Obama called the situation at the southern U.S. border a “humanitarian emergency”. Despite this assessment and a number of awareness campaigns and anti-smuggling initiatives, the reaction of the U.S. and Mexico to the crisis was largely limited to enhancing their border control. In the summer of 2014, Mexico’s President Enrique Peña Nieto launched the so-called Plan Frontera Sur (Southern Border Plan), an extensive border protection program on Mexico’s southern border with Guatemala, which resulted in skyrocketing numbers of arrests and deportations of Central American migrants from Mexico. Mexico’s migration agency INM (Instituto Nacional de Migracion) deported over 175,000 migrants into the Northern Triangle in 2015 – two-thirds more than the previous year.

However, the number of Central American children reaching the U.S. border declined only briefly in 2015 as a result. It rose again in 2016 to 47,000, nearly reaching the levels of the 2014 crisis year. To many observers, this development was no surprise as the causes of child migration from Central America – violence, poverty, family ties in the US, and sophisticated smuggling services – remain unchanged. It is therefore likely that Central American children and adults, despite deterrent measures and rising investments in border protection, will continue in the coming years to attempt to leave their home countries and travel north.

3. “Perceived Truth” and Political Calculation: Why the U.S. Political Discourse Avoids Basic Migration Facts

Put bluntly, migration from Mexico to the U.S. is old hat. The statistics described here – declining Mexican and simultaneously rising Central American migration – is clear. But they go largely unmentioned in the current public and political debate in the US. President Donald Trump’s assertion that it is necessary to build a wall to deter illegal immigrants from Mexico disregards the fact that illegal migration across the southern U.S. border reached a 40-year low in 2015.

What explains this disregard of fundamental migration facts in U.S. political discourse? Four factors are involved.

First, migration “perceived” at the local level is not determined by statistics and the actual number of migrants. People do not experience immigration at the national level but at the local level in the form of concrete circumstances, such as the ethnic mix at the school their children attend or the people they see every day on the streets in their communities or cities. The subjective perception of the migration situation in a country can therefore differ greatly depending on whether someone lives in the city or in the countryside, or whether the neighbourhood is traditionally ethnically diverse as in New York City or homogenous as in Salt Lake City.

Second, it is not so much the number of migrants but the speed with which migrants change the demographics of a place that determines how migration is perceived. Immigrants to the U.S. increasingly no longer settle only in the traditional immigration states of California, Texas, and New Mexico, but also in areas where locals previously had little experience with immigrants. The proportion of migrants arriving in South Carolina, for example, rose by 87 per cent between 2000 and 2012; the figure was 83 per cent for Alabama and 77 per cent for Tennessee. The faster migration changes the demographics of a place, the more likely people are to respond with scepticism. There are parallels to this phenomenon apparent in Europe. The Brexit vote several months ago indicated that voters in areas with large numbers of migrants were more likely to vote in favor of remaining in the EU (and for the freedom of movement for EU migrants this entails), while voters in areas where there had been particularly rapid demographic change through migration over the last few years were more likely to vote against remaining in the EU. Fear of migration appears thus more widespread where the number of migrants rises suddently, while a slower pace of change seems to cause less anxiety.

A third reason why U.S. voters continue to be concerned about this issue despite the historically low level of illegal immigration is the contrast between so-called flows and stocks. As explained earlier, over eleven million people are living in the U.S. illegally, including six million Mexicans. Even though the number of Mexicans attempting to enter the country illegally (flows) is declining in recent years, the overall number of Mexicans already living in the country illegally (stocks) is so high that it continues to perpetuate the engrained narrative of undocumented Mexicans.

Fourth and last, Donald Trump’s election shows that it can be politically opportune to avoid certain facts. Trump and his advisors succeeded in purposefully stoking the issue of illegal immigration to generate political capital. Here too, there are obvious parallels in Europe. Anti-immigration slogans and xenophobic rhetoric are among the basic tools used by many (albeit not all) populist parties in Europe. Populism presents a simplified view of the world, in which corrupt elites on the one side and honest people on the other side are pitted against each other, and complex problems can be solved through simple common-sense solutions. In this world view, immigrants represent the ideal scapegoats as they can be depicted as both not being part of the people and supposedly easy to get rid of – be it through entry bans, deportations or, in this case, walls.

4. The Future: Approaches Between Building Walls And Fighting Root Causes

Discussions on immigration in the U.S., Germany, and other popular destination countries regularly revolve around a key question: what approaches and policies are useful and effective in curbing unwanted or illegal migration flows?

Two frequently opposing political camps and philosophies answer this question differently. Proponents of extensive border protection measures, including wall construction, frequently get into heated arguments with proponents of investments in countries of origin and fighting root causes of immigration and refugee flows. Which approach dominates the debate in the U.S. and what do we know about the effectiveness of these two approaches?

Wall Construction and Border Protection in the U.S.

Border protection has been high on the political agenda in the U.S. since the 1990s and even more so since 9/11. The annual Border Patrol budget increased nine-fold between 1994 and 2015, from 400 million to 3.7 billion U.S. dollars (cf. fig. 4). The number of border patrol agents also rose sharply in the same period, from some 4,000 to over 20,000. Overall U.S. spending on enforcement of migration legislation to include border protection measures in 2012 is estimated at a whopping 18 billion.

Source: Own illustration based on CBP 2016, Enacted Border Patrol Program Budget by Fiscal Year, in: (28 Feb 2017); idem 2016, U.S. Border Patrol Apprehensions From Mexico and Other Than Mexico (FY 2000-FY 2016), pp. 2–3, in: (28 Feb 2017).

These massive investments are the result of decades of policies, supported by both Republicans and Democrats, that viewed enforcement as the main answer to waves of illegal immigration. Since the mid-1990s, the U.S. has constructed several walls and fences along the border. Some of these run through highly populated urban areas, others through barren countryside. The construction varies between concrete walls and iron bar fencing. The only thing all the border fortifications have in common is that they do not cover the entire border, but stop somewhere along its length.

Strengthening border protection has always been seen as a way to hopefully curb illegal immigration.

How Effective Are Walls and Border Protection?

Building walls is an extreme form of border protection, but countries use a variety of means of protecting their borders. Typical border protection measures include identity checks at entry points and in the vicinity of the border, which are carried out by border officials and/or electronic equipment at airports, ports, and other border crossings. Increasingly, this involves technical devices such as cameras, ground sensors, motion detectors, and drones.

Walls and border protection measures function on two levels. For one, they can block existing migration flows; and secondly, they can act as deterrents to potential future migrants, which means that they can – at least in the short term – help push down migration figures. There are many examples of this dynamic. In the U.S., rising border protection investment in the 1990s occurred parallel to falling apprehensions of undocumented immigrants at the border (cf. fig. 4). And when more and more European countries introduced border controls and constructed walls along the Balkan route in recent years, the number of refugees and migrants arriving in Germany declined.

These examples suggest that walls can successfully curb illegal migration – but that is not necessarily the case. There are three factors making it difficult to obtain a clear picture about the true efficacy of walls and border protection. In the first place, the effect of walls cannot be measured unequivocally. Even if apprehensions of undocumented migrants decline following wall construction and investments in border protection (as happened in the U.S. in the 1990s), other circumstances may have played a role, such as an economic recession (like the 2008/09 recession in the U.S.) or changing living conditions in the countries of origin (for instance in Mexico in recent decades). Other factors, such as the setting up of legal migration routes, for instance by granting temporary work or student visas, can also influence the flow of undocumented migrants to a country, as can changes to the border protection regimes of other countries in the region. Second, a fundamental dilemma for border protection is that more border patrol agents can conduct more arrests even if the number of border crossing attempts remains relatively constant. Paradoxically, greater investment in border patrol personnel can even create the impression of more rather than less illegal immigration as more arrests are recorded. Thirdly, illegal immigration is not necessarily linked merely to illegal entry. As illustrated by the numerous so-called visa overstays in the U.S., migrants can enter a country legally, for instance on a tourist or temporary work visa, and then stay on in the country once the visa has expired. Border protection and wall construction have no effect whatsoever on this form of illegal immigration.

Walls and enhanced border protection measures also bring with them a number of problems and unintended side effects. For one, there are ways to bypass walls, particularly if they only cover part of the border as is the case in the United States. More or less creative solutions range from tunnels, ladders and ropes to ramps, catapults, and drones (e.g. for smuggling drugs).

Second, more border protection makes migration more dangerous. Even if walls are successful in blocking migration flows in the short term, they tend to displace rather than decrease them in the medium to long term. Border protection frequently moves migration routes to more hostile terrain – in the case of the U.S. to the desert. Here, the number of deaths per year rose from below 100 in the early 1990s to almost 500 in 2005. A similar dynamic can be witnessed in the Mediterranean in recent years. While the number of migrants trying to cross the Mediterranean in 2016 was much lower than at the height of migration flows the previous year (some 360,000 in 2016 compared to over a million in 2015), the number of fatalities rose from just under 3,800 to over 5,000 in the same period. Data from the UNHCR show that the roughly ten kilometer long sea route from Turkey to Greece, the main route in 2015, claimed substantially fewer lives than the considerably longer and more hazardous route from Libya to Italy, which was used much more frequently the following year.

Greater border protection can also result in smugglers increasing their prices and adapting their business model. According to estimates, the average price for a migrant to be smuggled from Mexico to the U.S. of around 500 U.S. dollars in the 1980s had risen to almost 2,500 U.S. dollars by the mid-2000s. In addition, people smugglers in Central America increasingly offer their clients three illegal entry attempts for the price of one. If a migrant is apprehended and deported back to his or her home country, he or she has another two attempts left without incurring additional financial cost – a business model that further exacerbates the so-called revolving door problem (of migration, deportation and remigration).

A fourth side effect of border protection is that it can cause circular migration to turn into permanent migration. For decades, Mexican immigration was characterised by seasonal or circular labor migration; but the more difficult it became to cross the border, the more Mexicans and their families felt inclined to settle in the U.S. permanently. In 2014, eight out of every ten undocumented Mexican immigrants had already been in the U.S. for over ten years.

As this analysis shows, walls and border protection can indeed be effective symbols of deterrence, shift flows of migration, and therefore help to temporarily curb migration – but they do not resolve the problem of illegal immigration in the long term or completely, and entail considerable problems and undesirable side effects.

How Effective Are Measures to Fght Root Causes?

On the other side of the debate is the approach of fighting root causes of migration. Seeing that many migrants around the world do not leave their home country voluntarily, but because they feel compelled to do so due to destitution or armed conflict, fighting root causes and providing development aid for countries of origin seem to be a logical strategy for reducing migrant flows.

Mexico is, in fact, an excellent example of a country where improved economic conditions have contributed to a strong decline in emigration. Mexico’s gross domestic product (GDP) has grown by an average of 2.5 per cent over the last ten years. Between 2001 and 2011, the proportion of Mexicans belonging to the middle class increased by close to nine percentage points, with over ten million Mexicans rising up into the middle class. Over the same period, annual apprehensions of undocumented Mexican migrants dropped from 1.2 million to 290,000. Surveys show that Mexicans report increasing levels of satisfaction with their lives in their country; in 2015, a third of surveyed Mexicans stated that life in Mexico was neither better nor worse than life in the U.S. – a rise of ten percentage points compared to 2007.

Improved economic conditions in Mexico have contributed to a strong decline in emigration.

So, does the development of origin countries stop migration? Not necessarily. Despite the example of Mexico, the idea that economic progress in a country automatically reduces migration from that country is a classic migration myth – widespread but wrong. Studies show that for poor countries with a low GDP (below approximately 6,000 to 8,000 U.S. dollars) the rule of thumb is in fact as follows: the richer they become the more this stimulates migration. Why is this the case? One reason for this phenomenon is that people with more disposable income are more likely to have the necessary resources to emigrate – because it is often not the poorest who migrate but those who are in a position to save up starting capital and/or travel and potential smuggler costs. Furthermore, as countries develop, their child mortality rates decline, which means the pool of potential future emigrants increases.

It also has to be said that investments in a country’s development are, of course, not always successful, and even when they are, their effect may only be felt in the long run – a classic dilemma of development cooperation. The U.S. has been investing in the development of Central America for decades, but deep-rooted problems such as corruption, poor education systems, the power of gangs, and the extreme poverty of large parts of the population still act as strong drivers of migration. It remains to be seen to what extent the latest development program for Central America, the so-called Alliance for Prosperity, which was presented by El Salvador, Guatemala and Honduras in 2014 in response to the child migration crisis and which the U.S. supports with close to 750 million U.S. dollars, can achieve a breakthrough. In any event, positive effects will take a long time in developing – as opposed to the short-term achievements expected of politicians.

In sum, fighting root causes can reduce unwanted migration flows, but it can only be effective over the long term and not necessarily in every case; in particularly poor countries, it may even stimulate migration.

5. Conclusion: From Zero Sum Game to Compromise Solution

Political discussions focusing on the extremes suggest (both in the U.S. and Germany) that border protection and the fight against root causes are fundamentally different approaches to reducing migration. Some advocates of border protection consider the fight against root causes a “soft” approach that is neither promising nor urgent, while conversely some advocates of fighting root causes argue that border protection is unethical and that walls are ineffectual in any case.

This analysis has shown that this dichotomy does not match the facts. Walls and border protection can only represent short-term and partial ways of curbing migration flows; investments in root causes, on the other hand, only have long-term and partial effects. Genuine solutions are therefore policies that combine both approaches – compromise solutions. Sustainable migration policies entail both border protection measures and efforts to fight root causes, and treat the two concepts not as a zero sum game but as necessary components of effective migration policies.

Neither the best border protection measures nor the best efforts to address root causes can fully stop unwanted migration flows. Mature migration policies must therefore be capable of balancing and merging both approaches.


Victoria Rietig is Senior Migration Fellow at the American Institute for Contemporary German Studies (AICGS), Johns Hopkins University, Washington, D.C.

Christian Bilfinger is Trainee at the Konrad-Adenauer-Stiftung’s office in Mexico.

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