Encyclopedia of Security and Emergency Management

Living Edition
| Editors: Lauren R. Shapiro, Marie-Helen Maras

Border Security

  • Keith CozineEmail author
Living reference work entry

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DOI: https://doi.org/10.1007/978-3-319-69891-5_11-2


Borders Security Transnational Threats Smuggling Trafficking Migration Counter-terrorism Travel documents Passport Control Baggage Control Ports of Entry 


Border security is the step that nations take to prevent people or items from entering and departing into their country that may pose a threat or other adverse consequences or otherwise violate that nation’s laws.


One could argue that borders have been around since humans first began to settle in fixed locations, claiming that location as their own. As humans moved from hunter-gathers to agrarian society, they began to mark land over which they believe to have exclusivity over its use. These lines of ownership or borders could exist only in one’s mind, meaning that this is what this person or group of people believed to be theirs, accepted by others outside their borders, based on physical features of the earth, or barrier such as primitive fences or walls to mark their land. Today, borders most commonly thought of as the divide between political entities, usually between countries. Just like in early times, these borders could be imaginary, existing only in the mind of certain individuals, borders that are agreed upon, and demonstrated by lines on a map based on conquest, threat, agreements with others, natural physical feature, or walls and other means of marking territory. Just like early man marking their territory, borders have become a symbol of national sovereignty where that nation exerts exclusive control. Borders represent national sovereignty that need to be protected and controlled to maintain that country’s sovereignty; therefore, border security is an important component of any country’s national or homeland security (Phelps et al. 2014).

Throughout much of history, the primary threat to border security was military incursion from hostile neighbors or other foreign forces. In fact, just a quarter of a century ago, what Winston Churchill famously referred to as an “Iron Curtain” divided Europe between East and West. The North Atlantic Treaty Organization (NATO) was founded at least in part in response to the threat posed by the Soviet Union and Soviet expansionism. As a result, in many parts of the world, much of what would be considered border security was handled by countries’ military organizations (Cozine 2016). However, the use of military power against another state may no longer be the practical option if these two opponents are both militarily and economically powerful. The cost of war can become a high one, not just in the cost of lives but also the harm done to both nations’ economy, as well as the global economy.

Today’s globalized world seems to continually shrink to a point where time and space are less and less important. Advancement and innovation in shipping allow for goods to be loaded onto ships, cross vast oceans, and then be unloaded and delivered to markets in days. Air travel, which not long ago was available only to the elite, is now affordable to all but the world’s poorest. This current era of globalization has been decades in the making. However, few argue with the notion that the end of the Cold War and East-West divide was a catalyst, speeding up the process and bringing its benefits to the world as a whole. Advancements in technology and transportation that facilitate more efficient and faster trade and travel have not exclusively benefited legitimate transnational actors but have has also benefited international criminals, terrorist, and their organizations (Rees 2006). With globalization and the barriers lifted by the end of the Cold War, the security threat has shifted somewhat from state-centric threats to transborder issues such as financial collapse and global warming, pandemics, and threats from a variety of non-state actors. The openness that globalization has created engenders an environment in which the illegal trade of drugs, arms, intellectual property rights, and money is booming and has allowed for terrorist organizations to operate globally as well (Cozine 2010).


The terrorist attacks of September 11, 2001, and the way that those responsible were able to gain entry to the United States quickly focused the spotlight on border security as a major national security concern. Advancements in technology and transportation that facilitate faster and more efficient trade and travel have not exclusively benefited legitimate transnational actors; they have also benefited international criminals, terrorists, and their organizations (Rees 2006). The September 11th hijackers were able to take advantages of flaws in the US border security and visa system to pass through ports of entry, in some cases, several times, to train, plan, and carry out the attacks.

The attacks and the way that those responsible were able to gain entry to the United States quickly focused the spotlight on border security as a major national security concern. In order to better understand how the September 11th attacks occurred, the US Congress passed legislation that created the National Commission on Terrorist Attacks Upon the United States, more commonly known as the 9/11 Commission. The Commission was tasked with preparing a full and complete account of the circumstances surrounding the September 11th terrorist attacks. It quickly became apparent to the Commission that the terrorists’ ability to successfully gain entry to the United States was a key element in their ability to carry out the attacks. The topic of terrorist travel was deemed so important that it was covered in much greater detail in the form of a staff monograph separate from the Commission’s final report (Cozine 2010).

The profile of those individuals who pose the greatest threat, at least in terms of terrorism, has evolved over the past decade and now focuses on homegrown violent extremism – a threat that arises from within a domestic population where citizens or residents embrace an extremist ideology and take violent action in furtherance of that ideology (Southers 2014). Much has been made of the concept of the lone wolves, inspired to carry out terrorist attacks on their own, without any specific direction from a terrorist organization. In reality, the most catastrophic attacks and sophisticated plots were carried out in some part by members of the domestic population that traveled to other areas of the world to receive training and direction from terrorist organizations. This is a phenomenon that first came to light in the aftermath of the July 7 bombings in London and most recently played out in Paris and Brussels (Cozine 2016). This threat environment has created a situation where border security and those organizations charged with securing a nation’s borders now face the dual challenge of dealing with both homegrown and external threats. Traditional border security was focused on outsiders seeking to do harm – a concern that still exists today as highlighted by the June 2016 attacks at the Istanbul Airport that were carried out by attackers from Russia, Uzbekistan, and Kyrgyzstan who entered Turkey a month before the attack by illegally crossing its border with Syria carrying the suicide vests and bombs used in the attack (Karimi et al. 2016). However, there is also an internal threat of one’s own citizens traveling overseas to Iraq or Syria to join terrorist organizations and possibly return home to carry out attacks. Since 2011, nearly 40,000 fighters, including at least 6,900 from Western countries, have traveled to Syria. Around 250 of the Westerners traveled from the United States and 5,000 traveled from European Union countries. It is suspected that one third of the European fighters have returned home from Syria (House Homeland Security Committee 2016 June).

The reality is that terrorism is only one of the many man-made and natural transnational threats and challenges that face those tasked with securing a nation’s borders. Today, illegal migration, human smuggling, drug trafficking, counterfeit goods, and mass migration are just a few of the man-made threats the border security officials must combat. Add to this mix a variety of natural threats such as pandemics or invasive species and the threat picture becomes even more complex. Adding to this complexity is the question of how border security agencies and organizations provide security while still facilitating legitimate trade and travel across international borders, a process vital to the health of the global economy. Nearly 1 million people and 67,000 cargo containers enter the United States each day (Custom and Border Protection 2016). Finding those individuals or items that pose a security threat among this avalanche of people and goods that cross the border each day is truly a daunting task. But the nature of borders and the strategies for securing them are as varied as the threats that are faced.

Nature of Borders and Border Security

Borders can take many forms: natural, such as rivers and other bodies of water; physical, such as walls and fences; agreed upon lines on a map; or any combination of these. How well border security and integrity are maintained directly affects those living within those borders and those who wish to profit from violating internationally accepted rules of national sovereignty. The characteristics of borders are often dictated by societal and political institutions within a particular country as well as their relationships with their neighbors and potential threats that lie just on the other side of that border (Cozine 2016).

Natural borders will often dictate a country’s border security strategy. Geography has long been a barrier that has separated people into separate groups, and even today these mountains remain as a physical and political border separating China from Pakistan, India, and several other countries. The Alps have long served as an impressive physical border in Europe. The Alps have allowed for Switzerland to maintain independence political neutrality since 1291 and has not been in a state of war since 1812. This, despite the fact that during this time there has been a state of near constant hostility all around them, including two world wars. Bodies of water have also served an import physical barrier that separated people and established political borders. The English Channel has separated Great Britain from the European continent, thus allowing Britain to implement many policies separate from those of the European Union including maintaining border control between itself and the rest of the continent. The oceans, seas, and other large bodies of water remain formidable barriers. For proof, one needs to look farther than Australia and New Zealand, two large island nations that have never been invaded.

When natural barriers do not exist between countries and one country sees its neighbors or things within its neighbor’s borders as threats, many countries feel the need to fortify borders with artificial barriers to prevent or limit unwanted incursions across the border. The most common artificial barrier between nations are walls. Walls are erected to prevent or deter an individual, groups of people, even foreign forces from crossing a nation’s border or designed to funnel legal border crossings through checkpoints or ports of entry setup at specific locations. Walls are not the only type of artificial barriers used to fortify borders. Other types of barriers include fences, armed patrols, and air and marine patrols. Increasingly, technology is being implemented either in lieu of artificial barriers or to augment both artificial and natural barriers. These include measures such as motion sensors, thermal image cameras, and even unmanned aerial vehicles, all of which can be monitored remotely by user who can dispatch a response team to deal with unwanted border incursions (Phelps et al. 2014).

Border security is not exclusive to the geographic location where one country meets another. Individuals and goods entering a country legally need to enter that country through a port of entry. Ports of entry are specific locations where individuals and goods can enter a country legally by land, sea, or air. They typically have a staff of people who check passports and visas and inspect luggage to assure that contraband is not imported and that individuals who are not eligible to enter a country or pose security risk are refused access. Ports of entry at international airports are usually divided up into two screening areas: passport control and baggage control. At passport control, it is individual people who are screened in terms of their eligibility to enter the country. Individuals are screened for things such as their citizenship, whether they have the required papers such as passport and visas if required, and whether there is something in the individual’s background that would make them ineligible to enter the county such as previous immigration violations, criminal record, or a danger to the security of that country. When an individual is ineligible to enter a country, they might try to sneak past passport control and border security officials by presenting fraudulent travel documents to change their identity or other characteristics about them such as their citizenship. There are a variety of types of fraudulent documents that an individual can use to try and gain entry to the country that they would otherwise not be allowed to enter. These include counterfeit documents; documents that have been altered in some way, such as switching the photograph or name; using a document that belongs to an individual who looks similar to the traveler, a technique known as impostoring; or using a genuine document that is real but has been obtained by identity theft or some other illegal means. This means that officials at passport control must very quickly determine an individual’s citizenship, whether they have the required documents, whether those documents are genuine, and whether the individual has anything in their background that would make them ineligible to enter the country. In recent years, many technological advances were introduced into the passenger screening process, including a variety of security features within the passport itself to aid in detecting counterfeits, radio-frequency chips that transmit information to border screening computer systems automatically, and increased use of biometrics such as fingerprint and facial recognition technology.

At baggage control, travelers’ belongings are screened for prohibited items, such as drugs, counterfeit merchandise, agricultural and food products as well as insects which may pose a risk to a country’s ecosystem, currency that needs to be reported, and items that require that a duty or other tax be paid. Screening at baggage control includes examining both the traveler and their baggage for prohibited items. Some common examples of how people try and sneak prohibited items through baggage control include hiding items in the lining or secret compartments of their luggage, making it look like other items such as prepackaged items and food products, sewing it into their clothing, simply strapping it on their body, or swallowing the drugs so that it passes through their digestive system after they have successfully entered through the port of entry. The only way for border officials to detect this type of smuggling is by the use of an X-ray machine. The reality is the way in which an individual can try and sneak prohibited items through baggage control is limited only by their imagination.

In addition to passengers and their baggage, many international airports also have large amounts of cargo pass through that all need to screen for prohibited items as well as cargo where duty needs to be collected. The same is true of seaports and ports of entry at land borders. At seaports, passengers and crew are screened for eligibility to enter the country, and cargo is inspected. What makes seaports somewhat different is the amount of cargo that comes in and out of seaports. One needs only to look at the enormous size of a modern container ship to have an idea of how much cargo passes through a seaport in a given day. For example, the Triple E container ship has a capacity equivalent to 18,000 20-foot containers that would fill more than 30 trains, each a mile long and stacked two containers high (Kremer 2013). Many ports of entry at land borders have to deal with a high volume of both individuals seeking admission (i.e., pedestrians or individuals in vehicles) and large amounts of cargo carried by tractor trailers or freight trains. Adding to the challenges is the fact that these conveyances themselves can be used to smuggle both people and prohibited items through a port of entry. The number of places to conceal both items and people on a large container ship is near limitless. Hidden compartments in cars, trucks, and trains have all been used to smuggle people and goods across the border in the past. This sheer volume of cargo and people coming through a port of entry on any given day makes providing for effective border security while at the same time facilitating efficient trade and travel a daunting task.

When nature does not serve as a mechanism for border security, the characteristics of border security are often dictated not just by societal and political institutions within a particular country but also the relationships they have with their neighbors as well as potential threats that lie just on the other side of that border. For an example of how internal politics and a volatile relationship with one’s neighbors impacts a country’s border security strategy, one needs to look no further than the Korean Peninsula and the demilitarized zone (DMZ) that is between North and South Korea. The DMZ is a 2.5-mile-wide and 160-mile-long barrier created by both countries surrounding the military demarcation zone that serves as the border separating the two countries since the end of the Korean War in 1953 (Phelps et al. 2014). With both countries’ militaries constantly patrolling their respective side of the DMZ while on alert for acts of aggression by the other side, the DMZ is the most heavily militarized border in the world with one side in a constant state of readiness to respond to threats from the other side (Phelps et al. 2014).

The nature of border security is not static and often changes over time. Perhaps no place in the world illustrates this better than Europe. Just a quarter of a century ago, what Winston Churchill famously referred to as an “Iron Curtain” divided Europe between East and West. Much like the border between North and South Korea, the Iron Curtain separated members of the North Atlantic Treaty Organization (NATO) on one side and Warsaw Pact members on the other. With the fall of communist regimes in Eastern Europe, it is now possible to drive from Spain to Finland without passing through a single border check. In reality, even before the fall of communism, the elimination of internal borders between democracies in Western Europe while at the same time strengthening their common external borders has been a goal in many European countries.

Since the 1970s, countries in Europe have worked together on an intergovernmental basis to combat cross-border threats such as terrorism, drug trafficking, and illegal migration. By 1980, the frequency of this cooperation was a growing recognition that the freedom of movement throughout the continent was a key element to establishing a common internal market; it became clear that this type of informal cooperation was no longer adequate to address cross-border issues faced on the continent (Direction Générale des Douanes et Droits Indirects 2015). Since EU member states could not reach an agreement on how to formally deal with these issues, France, Germany, and the Benelux nations agreed that the territory among their states would be without internal borders. This border-free zone became known as the Schengen Area, which was named after the town in Luxemburg where the agreement was signed on June 14, 1985. On June 19, 1990, the Schengen member states (Adopted by the Kingdom of Belgium, the Federal Republic of Germany, the French Republic, the Grand Duchy of Luxembourg, and the Kingdom of the Netherlands.) signed the Schengen Implementation Convention (SIC) to formalize their agreement on how the rules of the agreement’s framework would be put into place. The convention called for the removal of checks at internal borders, common rules for crossing external borders, harmonization of entry and visa conditions, enhancement of police and judicial cooperation, and the establishment of a common information technology system for border security. By September 1, 1993, all Schengen members had ratified the convention and the agreement officially entered into force. The Schengen Area became a reality in the spring of 1995 when, with only a few exceptions, border checks were eliminated between signatory nations and a single external border was created where members carried border inspections with identical procedures based on common rules for visa and entry requirements as well as asylum rights (European Union 2009).

During the 1990s, several other EU member states signed on to Schengen Agreement, and the Treaty of Amsterdam brought the Schengen Agreement and subsequent acquis (Schengen Convention; agreement accession to the Schengen Convention by Italy, Spain, Portugal, Greece, Austria, Denmark, Finland, and Sweden; the decisions of the Executive Committee and the Central Group; and Union acts adopted by the European Parliament and/or the Council after the Schengen acquis was integrated into Union law.) into the framework of the EU. When the treaty entered into force on May 1, 1999, every EU member state was within the Schengen Area with the exception of the United Kingdom, which includes England, Wales, Scotland, Northern Ireland, and Ireland. Schengen, along with the establishment of the euro as a common currency, became shining symbols of the reality of European integration. Ironically, today because of threats of terrorism, transnational crime, and mass migration stemming from conflicts in the Middle East and other regions, some Schengen members have reinstituted border checks on their borders, and there are political movements in some countries calling for withdrawal from the Schengen zone.

Border Security in the United States

For the latter half of the twentieth century, the continental United States was long thought to be insulated from a massive attack other than a Soviet nuclear barrage. These all changed on September 11, 2001, when its vulnerability was revealed. While September 11 brought this vulnerability to the forefront, a variety of non-state actors have long benefited from the ever-increasing openness and interconnectivity of the world to operate across national borders in violation of law and evading law enforcement to achieve their goals (Andreas 2003). However, the September 11 attacks did result in a dramatic restructuring of the United States’ approach to both border security and intelligence. The Homeland Security Act of 2002 created the Department of Homeland Security (DHS) and, within it, Customs and Border Protection (CBP), which is the agency primarily responsible for border security in the United States at and between ports of entry.

Border security enforcement is the responsibility of three operational components within CBP: the Office of Field Operation, US Border Patrol, and Air and Marine Operations. The Office of Field Operations is primarily responsible for screening individuals and goods at air, sea, and land ports of entry. The US Border Patrol is the component whose main mission is to detect, interdict, and prevent individuals entering the United States illegally or smuggling people or contraband between official ports of entry. The Air and Marine Operations provides an air and maritime force to support the other two operational components by detecting, interdicting, and preventing the unlawful movement of people, illegal drugs, and other contraband toward or across the borders of the United States.

In addition to CBP, other agencies within DHS play an important role in border security: Immigration and Customs Enforcement (ICE), Citizenship and Immigration Services (CIS), and the US Coast Guard (USCG). Like CBP, ICE was created as part of DHS with the passage of the Homeland Security Act of 2002 and is the largest investigative organization within DHS by incorporating and consolidating the investigative elements of the former US Customs Service (USCS) and Immigration and Naturalization Service (INS) into one agency. ICE has two main operational components that carry out the daily enforcement and investigation activities—Enforcement and Removal Operations (ERO) and Homeland Security Investigations (HSI). ERO is primarily tasked with interior enforcement of immigration laws including identifying, apprehending, detaining, and removing aliens residing illegally within the United States or other aliens deemed removable by an immigration judge. HSI is responsible for investigating a wide range of domestic and international activities arising from the illegal movement of people and goods into, within, and out of the United States. CIS is responsible for overseeing lawful immigration to the United States while also maintaining the integrity of the country’s immigration system. The USCG is unique in a number of ways including that it is the only component of the US Armed Forces that is not housed within the Department of Defense, but rather it is part of DHS; it simultaneously acts as a military service, a law enforcement organization, and a regulatory agency. Included among the USCG’s many missions are defending the United States’ maritime borders by disrupting and deterring the flow of illegal drugs and undocumented migrants at sea, and preventing their entry via maritime routes to the United States.

There are also a variety of law enforcement agencies outside of the DHS that play a role in border security intelligence. Within the Department of Justice (DOJ), there are two such organizations – the Federal Bureau of Investigation (FBI) and the Drug Enforcement Administration (DEA). The FBI is involved in investigating a wide variety of issues directly related to border security, including international terrorism, human trafficking, and organized crime. The DEA’s primary mission is to investigate and prepare for the prosecution of major violators of controlled substance laws operating at interstate and international levels. The Department of State’s (DOS) Diplomatic Security Service (DSS) is another law enforcement agency that is directly involved with border security. In addition to its protective mission, DSS also investigates passport and visa fraud.


A country’s border security strategy varies greatly depending on that country’s geographic location, political institutions, and social and cultural heritage. For example, the border the United States shares with the Canada is the world’s longest undefended border, stretching nearly 9,000 kilometers across land and water, yet there are still ports of entry and other security measures along (Phelps et al. 2014). This is in stark contrast to the borders of countries in the European Union where there are no border checks when crossing between many member states. On the other side of the spectrum is the heavily militarized border between North and South Korea. Complicating the matter further is the fact that borders and approach to border security are not static and will often change as one country’s relationship with their neighbors change and events occur in that neighboring country that directly impact the security of one’s own border security.

The fact is that no country can effectively go it alone when it comes to border security. In an ever more globalized world, what happens inside your neighbors’ borders impacts your own. Today, the threat to security does not just come from citizens of some far-off country that follow a particular violent ideology or make a profit by exploiting a country’s laws and weaknesses in border security measures to engage in illicit trade but one’s own citizens traveling overseas to carry out similar activities. Another major challenge is how a country, or groups of countries, provides border security while facilitating the efficient movement of legitimate trade and travel. For border security to be effective in confronting the diverse cross-border threats faced today, cooperation is needed not just with domestic partners with border security responsibilities but also with international partners to ensure the integrity and security of their borders and the safety of their people.



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Further Readings

  1. Andreas, P., & Biersteker, T. J. (2014). The rebordering of North America: Integration and exclusion in a new security context. New York: Routledge.CrossRefGoogle Scholar
  2. Koslowski, R. (Ed.). (2011). Global mobility regimes. New York: Palgrave MacMiollan.Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.College of Professional StudiesSt. John’s UniversityNew YorkUSA