E.g., 04/25/2024
E.g., 04/25/2024
Countering Terrorist Mobility

Countering Terrorist Mobility

In 2003, the Department of Homeland Security (DHS) was established as a response to the apparent ease with which terrorists entered the United States to plan for and carry out the September 11, 2001, terrorist attacks. One of the department's main tasks: improving border security.

Now the topic of border management is at the center of the political debate on immigration reform. This is occurring at a time when national counterterrorism strategy itself is being updated, and a strategy for constraining terrorist mobility will be forthcoming from the National Counterterrorism Center (NCTC), which President George Bush created in August 2004 to centrally analyze and collect terrorism-related intelligence and exercise coordinating management over strategic counterterrorism planning and operations.

These circumstances create a need and a valuable opportunity to examine how counterterrorism strategy relates to border security and immigration reform, and how terrorist mobility could be countered.

Immigration Policy and Terrorism

The first step is to recognize that while public discourse tends to equate immigration reforms with blocking terrorists' ability to travel, terrorist mobility comprises a set of problems distinct from, although clearly linked to, the phenomenon of global migration and the problem of controlling immigration to the United States.

Solving the domestic immigration problem requires a democratic consensus about the level and criteria for immigration, taking into account the economic, social, and political forces that drive immigration. It means striking a balance among competing concerns over national cohesion, economic impact, a spectrum of human rights issues, compassion toward refugees, human trafficking, and constitutional order. The balance of social unity, prosperity, and justice matters immensely to the country's security and legitimacy.

Prevailing over enemies that use terrorist stratagems, however, compels the United States to focus on small, elusive groups and individuals who circulate globally and whose agenda is to harm U.S. citizens and damage infrastructure to force changes in U.S. policy. Both migration, with its large-scale movements and periodic eruptions, and terrorism, with its devastating attacks, demand long-term responses.

But migration of the many and terrorism by a few must first be distinguished before the most effective policies and tactics toward terrorism can be developed. That some of these will overlap in practice does not lessen the need for separately considered approaches and measures of success.

Thus, the second step toward improving the United States' ability to constrain terrorist movements is to establish terrorist mobility fully and formally as an independent functional component of counterterrorism. It could be viewed as analogous to the approach to terrorist finance, receiving the same kind of broad attention from thinkers and practitioners. As a subfield of counterterrorism, terrorist mobility encompasses the study of terrorist movements, and how to both counter and exploit them.

The nature of terrorist movement can best be described in response to a series of key questions:

  • How is the terrorist travel function managed — by a terrorist travel facilitator or by arrangements with illicit travel organizations?
  • What are the global geographic routes and transportation practices?
  • What are the illegal entry and residence tactics in the United States — both the legal channels used illegally and the illegal channels?
  • What are the geographic variations in the use of legal and illegal channels?
  • How do terrorists interact with the illicit travel infrastructure that supports migration outside legal channels and crime?
  • What are the legal and cultural safeguards that nations and peoples develop for immigration and citizenship and other political or social factors that may inhibit or support terrorist mobility?

Moving Toward a Terrorist Mobility Strategy

All but the most recent of the national strategies the government has published since 9/11 — the most important of which address national security, homeland security, combating terrorism, and military-related homeland defense — omit mobility as a distinct functional element of terrorism requiring its own operational strategy. National strategies are important because they articulate what the country stands for and the risks it faces, and provide direction and guidance in acting on those principles and against those dangers.

Whatever other issues may be debated concerning current U.S. strategies — and these strategies have evoked a range of responses — there can be no room for debate that countering terrorist mobility deserves to be included as a strategic operational element of counterterrorism. This is particularly true since Congress, in the Intelligence Reform and Terrorist Prevention Act of 2004, set forth requirements for an initial strategy to constrain terrorist mobility.

A terrorist mobility strategy (TMS), meaning a strategy that aims to prevent terrorists from entering the United States, would have three broad purposes:

  • defensive — securing transportation, entry, and immigration channels against undetected terrorist movements and against attacks;
  • offensive — exploiting the potential exposure created by terrorists' need to move people and material to disrupt them; and
  • deterrent — raising the risk of global movement so that it becomes a factor in dissuading terrorists from attack.

Most policy discussion has focused on the first, defensive homeland-security purpose. And indeed, conceptually and practically, the three purposes overlap. For instance, an active defense by U.S. border authorities does not passively await the approach of a terrorist or rely on hardened perimeters. Instead, it seeks to dismantle criminal travel networks through transnational criminal investigations and intelligence operations; to reduce the vulnerability of legal travel channels through global efforts to raise travel document security standards; and to support the offensive tracking of individual terrorists using intelligence, border inspections, and information analysis, among other actions.

The continued threat from Islamist terrorist groups is the obvious justification for a terrorist mobility strategy today. The mobility tactics used by Al Qaeda and its predecessors, both in the successful 9/11 attack and previous attacks against Americans in the United States and abroad, continue to be relevant. Entry from Canada with the support of Islamist cells there, embarkation from U.S. Visa Waiver Program countries in Europe, surreptitious entry from Mexico through human smuggling channels, and recruitment and transportation in the United States are all serious issues for a terrorist mobility strategy.

While much attention has been focused on the southern border, the United States' security relationship with Canada is especially important, as suggested by proximity, less restrictive travel regulations, and the scale of Canada's terrorist presence. Similarly, the security relationship with Europe is especially important because of the violent Islamist factions there, as well as more lenient travel regulations for EU citizens.

The intention here is not to refine priorities but to assume a broad vulnerability through all potential points of entry and exploitation of the U.S. immigration system, and explore a general approach to addressing both.

A strategy to undermine and disrupt terrorist mobility would require the following:

  • Establishing high standards of knowledge of terrorist mobility;
  • Targeting terrorists who act as travel facilitators;
  • Aggressively working to shrink and exploit the illicit travel networks (e.g., document providers, human smugglers and traffickers, and other transnational criminals) that are a source of travel facilitation and funds for terrorists;
  • Investing in the ability to track individuals en route;
  • Equipping legal entry and immigration channels to better detect terrorists;
  • Denying terrorist access through illegal entry channels;
  • Creating a systematic approach to constraining terrorist mobility within the United States; and
  • Conducting thorough, post-incident and post-attack terrorist mobility reviews that enable preventive measures to be strengthened and public confidence to be bolstered.

Each of these elements would need to be effectively integrated and continually improved. While the United States has a greater obligation to secure its own entry channels, the job becomes exponentially more difficult — even impossible — without security partnerships with neighbors and allies, greater security within their borders, and greater security of common global travel and trade pathways. This necessitates a greater emphasis on terrorist mobility related diplomacy and leadership in the development of new laws and processes internationally.

It is an oversimplification to conceive of the job of preventing terrorist infiltration as a competition between resources allocated to generic "border security and immigration controls" on the one hand and to "intelligence" about terrorists on the other.

The border, transportation, and immigration systems are themselves venues for significant development of knowledge, rules, and processes with which to counter terrorist mobility; for operations against terrorist travel facilitators; and for the application of methods of terrorist detection that go well beyond watch-list use. Development of these measures would strengthen U.S. defenses against terrorists — including through support to offensive operations — and also generally reduce the vulnerability of border and immigration systems.

Weaknesses in the Current Approach

While there are well-established and highly effective programs already focused on terrorist movements, there are some notable weaknesses in U.S. efforts so far. These largely mirror challenges facing the overall counterterrorism effort.

Limitations are particularly evident where innovation and nontraditional relationships are called for in and among governmental functions. For example, there is a need for

  • greater infusion of classical intelligence and investigative practices into the border control and immigration systems (analogous to the need to dismantle the "wall" between law enforcement and the intelligence community);
  • central compilation and analysis of immigration law investigation information;
  • the sharing of information between the law enforcement community and analytic units in the homeland security and intelligence community; and
  • expanded terrorism-related crime control that bridges the United States and foreign countries.

Most importantly, the knowledge and effective activities that do exist would need to be integrated and deployed for maximum impact. Tactics to gain insight into and disrupt terrorist movements can be optimized only by simultaneous employment of all of these operational levers.

Direction, management, and the supporting organizational structures are critical for designing and carrying out such a complex task. Although some key elements are in place, they are not yet sharply defined or authoritatively developed. For example, top officials are not yet provided with a baseline report that lists suspected terrorist entries and stays by location, channels, transit paths, and detection and confirmation methods. Only the new National Counterterrorism Center has the potential to ensure the standardized compilation of such basic data, which must come from a range of agencies.

In terms of organizational structure, the government does not yet have a way to systemically scrutinize terrorist travel documents, investigate suspected terrorist entries and illegal residence, or carry out transnational investigations of and operations against terrorist travel facilitators. A key area of ambiguity is the Department of Defense's role in terrorist mobility countermeasures at U.S. borders, within the United States, and globally.

For the foreseeable future, insufficient integration of assets is the most fundamental problem. The structural advantage of having established DHS is that it consolidates agencies with authority in the U.S. border and immigration zone, a legally and geographically distinct arena in which terrorist vulnerabilities can be effectively exploited and vulnerabilities reduced.

But with respect to terrorist mobility, DHS has an ambiguous and problematic relationship with the Federal Bureau of Investigation (FBI), which is the designated but struggling domestic counterterrorism agency. Also unclear is how DHS will be integrated into a globally networked counterterrorism effort in a structure in which the Department of State leads foreign policy and the NCTC directs counterterrorism.


Addressing the role of terrorist mobility at the highest levels of government would make it easier to closely tie the priorities and resources for countering terrorist mobility to the United States' larger terrorism agenda. Thus, mobility measures could be fully and carefully considered in designing policies and actions to deal with terrorists, dissuade state sponsors of terrorism, and construct comprehensive security measures for the border, among other measures.

In each discrete area, the United States could make significant progress by making terrorist mobility a more important consideration than it is today. If, at the highest level of national strategic and policy discussions, constraining terrorist mobility continues to be casually conflated with maintaining a functional and acceptable immigration system and effective border security — goals that are essential but different and dangerously limiting — the United States will continue to lose vital opportunities to defend, deter, and strike.

This article is based on the report "Countering Terrorist Mobility: Shaping an Operational Strategy," which was prepared for MPI's Independent Task Force on Immigration and America's Future, a joint effort with Manhattan Institute and the Woodrow Wilson International Center for Scholars. The full report (in PDF format) can be downloaded here.