Making Interior Enforcement Work

By Steven A. Camarota on June 19, 2002

Testimony prepared for the House Judiciary Committee
Subcommittee on Immigration and Claims
June 19, 2002

By Steven Camarota
Director of Research, Center for Immigration Studies


Interior enforcement is a critically important part of effective immigration control. Along with visa processing overseas, the borders, and ports of entry, enforcing laws within the United States is a key component of administering the nation's immigration laws. Unfortunately, for a long time, efforts to enforce immigration laws within the United States have been very limited. This has helped to create a very large illegal population, now estimated by the Census Bureau at more than eight million.1 Lax enforcement of immigration laws has also increased America's vulnerability to foreign‑based terrorists. Reinvigorating interior enforcement could play a vital role in reducing both conventional illegal immigration and the terrorist threat. In my testimony I will explain why interior enforcement is so important to the nation and suggest some possible ways to make it work better.

There are a number of reasons why interior enforcement must be improved. First, in a nation built on the rule of law, allowing any set of laws, including those pertaining to immigration, to be widely flouted undermines the very foundation of our republic. More specifically, there are significant costs to the U.S. economy and American taxpayers from allowing millions of people to live in the United States illegally. Finally, there is the risk from foreign‑born terrorists. In a study recently completed by the Center for Immigration Studies, we found that 22 of 48 al Qaeda‑linked terrorists who have been involved in terrorism in the United States between 1993 and 2001 had committed significant violations of immigration laws prior to taking part in terrorism.2 Thus, strictly enforcing immigration laws could become a key component of our anti‑terrorism efforts.

Why Illegal Immigration is a Serious Problem

Illegal Immigration is a National Security Risk. As already indicated, a number of terrorists violated immigration laws before they committed their crimes. In many cases these terrorists lived, worked, opened bank accounts, and received driver's licenses with little or no difficulty. They operated for extended periods within the United States while they were in violation of immigration laws. For example, of the 48 terrorists in the study cited above, at least 13 had overstayed a temporary visa at some point.

In addition to overstaying visas, we found in our study that terrorists have violated immigration laws in a number of other ways. Some terrorists have engaged in fraudulent marriages to American citizens, such as Fadil Abdelgani, who took part in the plot to bomb New York City landmarks in 1993, and Khalid Abu al Dahab, who raised money and helped recruit new members for al Qaeda from within the United States. Terrorists also violated immigration laws by providing false information on their applications for permanent residence, such as Sheik Omar Abdel Rahman, who inspired several terrorist plots. Still other terrorists have violated the law by working illegally in the United States; at least eight terrorists held jobs for extended periods while living in the country illegally before taking part in terrorism, including those involved in the 1993 World Trade Center attack, the plot to bomb New York landmarks, and the Millennium plot. Because such a large percentage of foreign‑born terrorists violated immigration law, enforcing the law would be extremely helpful in disrupting and preventing terrorist attacks.

Tolerating Illegal Immigration Facilitates Terrorism. One might reasonably point out that the vast majority of illegal aliens are not terrorists. However, allowing a large illegal population to reside in the United States facilitates terrorism for two reasons. First, it has created a large underground industry that furnishes illegals with fraudulent identities and documents that terrorists can (and have) tapped into. Several of the 9/11 terrorists were assisted in getting their Virginia driver's licenses from someone who specialized in helping run‑of‑the‑mill illegal aliens obtain them.

Second, the existence of a huge illegal population creates a general contempt or disregard for immigration law. Although the general public may still want the law enforced, the scale of illegal immigration creates a tacit acceptance by law enforcement, policymakers, and even the INS itself. With millions of illegal immigrants already in the country, and with immigration laws widely flouted, it is perhaps easy to understand why the immigration inspector at Miami's airport allowed Mohammed Atta back into the country in January 2001 even though he had overstayed his visa on his last visit and had abandoned his application to change status to vocational student by leaving the country.

The release from detention of 1993 World Trade Center Bomber Ahmad Ajaj, or Brooklyn subway bomber Gazi Ibrahim Abu Mezer, both of whom had no legal right to be in the country, does not seem so outrageous when one considers that immigration law is routinely violated and millions of people are allowed to live in the country illegally. Tolerating mass illegal immigration is by no means the only factor increasing the chance that terrorists will successfully enter and remain in the country, but by not enforcing immigration law we certainly made life easier for the large number of terrorists who had broken immigration laws in the past.

Illegal Immigration Imposes Significant Costs on the Economy. We know from a variety of sources that illegal aliens are overwhelming unskilled, with perhaps more than three‑fourths lacking even a high school education. Each year roughly one‑quarter of a million illegal aliens who lack a high school education settle in the United States. Allowing in so many unskilled workers creates very significant economic problems. The economic goal of a modern society such as ours is to create a large middle class through high‑wage, capital‑intensive jobs exhibiting growing labor productivity and aiming toward a flatter distribution of income. Mass unskilled immigration, a very large share of which is illegal, subverts these goals. In its 1997 report, the National Research Council concluded that by increasing the supply of unskilled workers, immigration was responsible for close to half the decline in relative wages for high school dropouts from 1980 to 1994, translating into lost wages for those dropouts amounting to about 5 percent of their incomes.3

From the point of view of employers, this seems like a desirable state of affairs, since lower labor costs mean higher profits, and for consumers it should mean lower prices as well. Of course, for the 10 percent of our workers who lack a high school education and who are already the lowest‑paid workers, this reduction is quite harmful. But, putting aside the impact on the working poor, the long‑term consequences of illegal immigration for the economy are also harmful.

There is strong evidence that in industries as diverse as construction, garment manufacturing, and agriculture an increasing reliance on unskilled illegal‑alien labor is slowing productivity gains and causing the United States to fall behind its international competitors. Unskilled immigration acts as a subsidy by artificially holding down labor costs by increasing the supply of labor. Businesses tend to want subsidies and often grow dependent on them. But like any subsidy, illegal immigration prevents innovation and causes the industry in question to lose its competitive edge in the long term. Reducing illegal immigration and allowing wages to rise naturally would not only be good for the working poor, it would make for a more productive economy. Employers, in response to upward pressure on wages, would adopt more productive methods, such as dried‑on‑the‑vine raisin production or greater use of pre‑fabricated material in construction. We can reduce illegal immigration secure in the knowledge that it will not spark inflation because unskilled workers account for such a tiny fraction of total economic output. High school dropouts account for less than 4 percent of total output in the United States, so even if wages rose substantially for these workers, the effect on prices would be very small.

Illegal Immigration is Also a Problem for Public Coffers. In addition to reducing wages for the working poor and hindering productivity gains, there is another problem with illegal immigration C it imposes significant fiscal costs. As a practical matter, the middle and upper class in the United States pay most of the taxes. The poor, immigrant or native, generally consume significantly more in public services than they pay in taxes. Because illegal aliens are overwhelming unskilled, this results in their having much lower incomes and tax payments. Moreover, while illegal aliens are not supposed to use most welfare programs, in fact they often make use of them anyway. Even if the immigrant himself is not eligible because of legal status, immigrant families can still receive benefits on behalf of their U.S.‑born children, whose welfare eligibility is the same as any other native‑born American.

In research done by the Center for Immigration Studies, we estimated that of households headed by illegal aliens from Mexico (the largest component of the illegal population), 25 percent used at least one major welfare program. This is lower than the 34 percent estimated for households headed by legal Mexican immigrants. But it is much higher than the 15 percent estimated for natives. Significant use of public services coupled with much lower tax payments means that illegal immigrants almost certainly create a net fiscal drain.

In 1997 the National Academy of Sciences (NAS) estimated that immigrant households consume between $11 billion and $20 billion more in public services than they pay in taxes each year. This net fiscal drain (taxes paid minus services used) is almost entirely the result of unskilled immigrants. The Academy estimated that an immigrant with less than a high school education imposes a net fiscal drain of $89,000 on public coffers during his lifetime. This burden on taxpayers would, of course, become even worse if these immigrants were legalized, because they would remain largely poor, given their limited education levels, but they would become directly eligible for welfare programs. From the point of view of taxpayers, reducing illegal immigration by enforcing the law would almost certainly be desirable.

What Can Be Done To Make Interior Enforcement Effective

Tracking System for Temporary Visa Holders. There is a longstanding problem that the federal government often has no idea whether foreign visitors have left when their temporary visas expire. In addition, it often has no idea where foreign citizens live while their visas are still valid. A number of terrorists have been tourists and business travelers, and it would be very difficult to track such individuals within the United States. Even in the current environment, it is unrealistic to expect all foreign visitors to submit their passports every time they check into a hotel and to expect hotels to report that information. Currently, foreign travelers are required to write down their destination upon entering the United States, but no effort is made to verify the information; in fact, two of the 9/11 jihadists listed "Marriott Hotel, New York" as their destination. Perhaps there is some practical means for tracking tourists and business travelers; developing such a system would certainly be a significant challenge, but it is something the INS should at least be studying.

While tracking tourists and business travelers may not be possible at present, it would be possible to track foreign citizens residing here for extended periods of time who are affiliated with an American institution responsible for their whereabouts. Such a system makes sense because many of these long‑term visitors (here from one to six years, or more) reside here for a long time in a legal status, whereas short‑term visitors are less likely to have the time to hatch sophisticated plots before their visas expire. Although short‑term tourists and business travelers, who are not attached to any American institution, make up the majority of non-immigrants, the number of long‑term visa holders requiring oversight is still quite large. In 1999, there were more than 923,000 foreign students and exchange visitors admitted (including their spouses and young children), up 45 percent just from 1995. And the number of long‑term foreign workers, plus family members, was approximately 1 million in 1999, up 123 percent from 1995. Tracking these individuals through their American institution is both desirable and possible. If they leave their schools, jobs, or otherwise violate the visa we would know it immediately, and then we could send out an investigator while the trail was still warm.

Tracking Foreign Students. One of the largest single categories of long‑term temporary visitors is foreign students (F1 and M1 visas). A number of terrorists originally entered on student visas, including Eyad Ismoil, a conspirator in the 1993 World Trade Center bombing, and 9/11 hijacker Hani Hanjour, and both were in the country illegally when they committed their crimes. Ismoil dropped out after three semesters and remained in the United States illegally, while Hanjour never even attended class. Both Khalid Abu al Dahab and Wadih el Hage originally came to the United States on student visas, later married Americans, and became naturalized citizens.

The 1996 immigration law mandated that the INS develop a computerized tracking system for foreign students to replace the current manual, paper‑based system. Unfortunately, the system has not moved beyond the pilot stage, and has only been tested in a couple of dozen southeastern schools, largely because of opposition from universities and colleges. Institutions have opposed it, fearing the extra administrative burden and also because they do not like the idea of treating foreign students differently from their American counterparts. But given the very real threats we face, tracking students makes perfect sense. Ideally such a system would provide the INS with real‑time information verifying a student's enrollment and immediately notify the INS if the student drops out or otherwise is not honoring the terms of his visa. The border security bill recently signed by the president will go a long way toward creating such a system. Of course, it remains to be seen whether such a system will be given the resources and political support it needs to be fully implemented.

Tracking System Should Be Expanded to Non-Students. There is no reason to limit the tracking system only to foreign students. There are an additional million temporary workers, trainees, and intra-company transferees who can and should be included in such a system. Expanding the new tracking system to cover both foreign students and foreign workers is needed to ensure that the system is as comprehensive as possible. INS enforcement then could follow up with the sponsoring employer or other institution as soon as it receives notice that the person is no longer honoring the terms of the visa.

An Entry/Exit System Is Needed for Effective Interior Enforcement. An estimated 40 percent of illegal aliens entered the United States originally on a temporary visas and then did not honor the time limit. Given the large number of terrorists who have overstayed, enforcing visa time limits could disrupt or perhaps uncover terrorist plots in the future. The first step to enforcing time limits is the establishment of an entry/exit system that would automatically record the entry and exit of all persons to and from the United States. Those who overstayed should be barred from ever entering the country again. The system would also allow the INS to identify overstayers who are still in the country. Such a system is provided for in the border security bill the president signed last month, and it is up to elected officials to ensure that it is properly implemented.

Names of Visa Overstayers Should Be Placed in a Criminal Database. In January of 2002, the INS announced that it was going to add to the FBI's criminal database the names of more than 300,000 illegal aliens who have been ordered deported, but whose departure the INS cannot verify. This is certainly a good start, but once a well‑functioning entry/exit system is in place, there is no reason why the names, photos, and fingerprints of all visa overstayers could not also be added to the criminal database (assuming we begin gathering such information on all visa applicants). In that way, if they are ever arrested for a crime or even pulled over in a traffic stop, they could be held by local police and then turned over to the INS. This could become a key component of interior enforcement. With 3 to 4 million visa overstayers living in the United States, there is no question that tens of thousands of them have some encounter with the authorities each year. Traffic stops and arrests are a significant opportunity to apprehend those in the country illegally, and we should take full advantage of them.

While adding visa overstays to the criminal database would help reduce illegal immigration, one may still wonder if it would ever be useful against terrorists. In fact, two of the 9/11 hijackers were pulled over in traffic stops in months preceding the attacks. In the spring of 2001, the plot=s ringleader, Mohammed Atta, received a traffic ticket in Broward County, Florida, for driving without a license. He had, by this time, overstayed his visa on his previous visit to the United States between June of 2000 and January of 2001, though the INS at Miami International Airport allowed him back into the country. Had a system of carefully tracking overstays and placing their names in the criminal database been in place, then we might have been able to apprehend Atta and perhaps avert the 9/11 attacks. Although he had not overstayed his visa, Ziad Samir Jarrah, who was on board United Airlines Flight 93 that crashed in Pennsylvania on 9/11, was issued a speeding ticket on September 9 in Maryland for driving 95 miles an hour in a 60‑mile‑per‑hour zone. Thus, even the most sophisticated terrorists in American history seem to have run afoul of the law prior to carrying out their plans.

For the INS to quickly take custody of visa overstayers detained by police, it would need more detention space and more agents assigned to interior enforcement. By adding the names of visa overstays to the criminal database, the INS would in effect enlist the help of thousands of local law enforcement officers.

Enforcing the Ban on Hiring Illegal Aliens. The centerpiece of any interior enforcement strategy has to be enforcing the prohibition on hiring illegal aliens. While worksite enforcement, as it is commonly called, may not seem to be important to national security at first glance, it is, in fact, vital to reducing the terrorist threat. In 1986, Congress prohibited the employment of illegal aliens, although enforcement was at first spotty and has been virtually nonexistent for most of the past decade. Although it is obviously directed at turning off the magnet of jobs attracting conventional illegal aliens, such worksite enforcement is also important for anti‑terrorism efforts. Gaining control of the border between crossing points is probably only possible if we dramatically reduce the number of illegal job seekers who routinely cross into the United States. If prospective illegal aliens knew there was no job waiting for them in the United States, fewer would try to cross illegally, making it easier to secure the border.

As already indicated, the estimated 8 million illegals now living in the country have also created a vast market and infrastructure for fraudulent documents. The existence of widespread fraud can only make it easier for terrorists to operate in the United States. In addition, it would be much harder for terrorists who overstay their visas to blend into normal life if finding a job is made more difficult. A number of terrorists have worked illegally prior to being arrested for terrorism. At least eight of the terrorists in our study worked in the United States illegally before being arrested. Of course, terrorists could still come with large sums of cash and try to live undetected, but doing so would be much harder if getting a job is much more difficult.

Worksite Enforcement Must Be Made Effective. There are two steps that are needed to make worksite enforcement effective. First, a national computerized system that allows employers to verify instantly that a person is legally entitled to work in the United States needs to be implemented. Employers would submit the name, date of birth, Social Security number (SSN), or alien registration number to the INS for each new hire. This information is already collected on paper as part of the Immigration Reform and Control Act of 1986, but is not used by the INS. After an instant check of its database, the employers would then receive back from the INS an authorization number indicating that the person is allowed to work in the United States. The authorization number would provide the employer an ironclad defense against the charge that they knowingly hired an illegal alien. Tests of such systems have generally been well received by employers.

Document fraud, of course, is widespread, but a computerized system would be a key tool in uncovering it. For example, a valid SSN that is linked to a different name and submitted to the INS, or a SSN and name that show up among numerous employers across the country, would both be indications that a worker is trying to skirt the law. The INS could develop procedures to identify potential problems of this kind. When a potential problem is identified, the INS would then go out to the employer and examine all the paperwork for the employee, perhaps conducting an interview with the worker and determine the source of the problem.

Dramatically Increase the Number of INS Investigators. Investigators from the INS are charged with such tasks as worksite enforcement, anti‑smuggling efforts, and combating document fraud. There are only approximately 2,000 agents assigned to interior enforcement for the entire country. This number must be increased dramatically. At present there are only the full‑time equivalent of 300 INS inspectors devoted to worksite enforcement year‑round, whose job it is to enforce the ban on hiring the five or six million illegal immigrants now working in the country. If the number of investigators was increased to the levels necessary, they could begin to visit employers identified by the verification system as having a potential problem, and additionally could randomly visit worksites to see that employers were filing the paperwork for each worker as required by law. Those employers found to be knowingly hiring illegals would be made to pay stiff fines.

It is not just in the area of worksite enforcement that more investigators could be put to work. The system of tracking students and perhaps other visitors requires that there be enough agents to locate those identified by the tracking system as having violated their visas. If we create a tracking system, for example, but there are no agents to investigate those who stop working or attending class, then a tracking system is almost meaningless. Failure to develop such a system means that millions of illegal immigrants will continue to work and live in the United States facing little or no penalty. Not only does this make a mockery of the rule of law, harm the working poor, and impose significant costs on taxpayers, it also exposes the country to significant security risks.

Enforce Employment Verification and Alien Registration. Most of the recommendations outlined above have dealt with temporary visa holders or efforts to reduce illegal immigration. More effective monitoring is also needed of permanent residents. A number of militant Islamic terrorists have been legal immigrants, including Sheik Omar Abdel Rahman, Siddig Ibrahim Siddig Ali (ringleader of a plot to bomb New York landmarks) and Mahmud Abouhalima, a leader of the 1993 attack on the World Trade Center. Until the early 1980s all non‑citizens living in the United States were required to register annually their whereabouts with the INS. This practice should probably not be revived in that form. Potential terrorists cannot be expected to dutifully send in their addresses. However, the employment verification system outlined above could be a very effective tool in locating non‑citizen legal immigrants. This is especially important when a person is placed on the watch list after he has entered the country. At present, there is often no way for the INS to know where that individual lives; however, the employment verification process would provide the INS with the last known employer for green card holders who work. Thus, if it became necessary to arrest or at least undertake surveillance of a non‑citizen, his last known employer would be a place to start. The verification system would in effect be alien registration, at least for those resident aliens who work.

The INS Must Integrate Databases. One reform that would be relatively easy to undertake would be for the INS to integrate its various databases. At present, separate databases are maintained for non-immigrants, immigrants, citizenship applications, and deportations. The INS needs to establish a single integrated file on each foreign citizen that uses a biometric identifier like a digitized fingerprint. This file would contain information from each step in the visa process, including each land border crossing, each entry and exit at airports, each change in status at school or work, each arrest, as well as any application for permanent residence. This file should be accessible to law enforcement and would remain open until the person becomes a citizen.

Prevent Illegal Aliens from Obtaining Driver's Licenses and Bank Accounts. One change that seems obvious is to make it more difficult for illegal aliens to get driver's licenses and open bank accounts. Bank accounts are important because they make it easier for people who work illegally in the United States to cash paychecks and transfer money abroad. Thus, by allowing illegals to open bank accounts we make it easier to be an illegal alien, which in turn can only increase illegal immigration. A foreign passport or consular registration card should not be enough to open an account in the United States. A person should be allowed to open an account only with a U.S.‑issued driver's license or state I.D. card. The key is to prevent illegals from getting driver's licenses. A number of the 9/11 terrorists were able to get licenses and open bank accounts with little difficulty. Virginia, which issued eight drivers licenses to 9/11 terrorists, only required that a third party attest to the fact that the license applicant is a state resident. This is a clear invitation for illegal aliens and terrorists to obtain driver's licenses.

All states must require birth certificates and other supporting documents for licenses. Unfortunately, a number of states do not carefully verify identity or eligibility for a license, and in fact some states now explicitly allow illegal aliens to get licenses. Not only do licenses make it easier to open bank accounts, licenses are also helpful when accessing government documents, looking for a job, renting motor vehicles, and of course boarding commercial airliners. If we are serious about reducing illegal immigration and protecting the country from terrorists, then doing a great deal more to prevent illegals from opening bank accounts and obtaining drivers licenses will have to be part of our efforts.

Amnesties for Illegal Aliens Have Helped, not Hindered, Terrorists. The existence of a large illegal population clearly creates a host of problems for the United States. Instead of enforcing the law, some have suggested giving green card to the illegals, thereby "eliminating" the illegal population. Of course, this would not solve the problem of future illegal immigration; after the last amnesty in 1986, the 2.7 million who were given green cards were entirely replaced by new illegal aliens within less than 10 years. While the events of 9/11 have significantly reduced political support for what had been growing momentum to grant amnesty to Mexican and perhaps other illegals, the idea will likely re-emerge at some point in the future. Some have even argued after 9/11 that granting amnesty would be helpful to national security because it would allow law enforcement to know who is in the country. For this reason some amnesty advocates have even taken to calling it a "registration" of illegal aliens. However, in the past, amnesties have helped terrorists, and not impeded them in any way.

Mahmud Abouhalima received amnesty under the 1986 Immigration and Reform and Control Act, by falsely claiming to be an agricultural worker even though he was a cab driver. Given the limited resources of the INS, it was not possible to investigate or even verify the stories of the millions of people who applied for amnesty. As a result, the vast majority who applied for the amnesty were approved. Issuing Mahmud Abouhalima a green card facilitated his terrorism because he could then work at any job he wished and was able to travel to and from the United States freely. In fact, according the October 4, 1993, issue of Time magazine, it was only after he received his green card in 1990 that he made several trips to Pakistan, where he received combat training. Thus, the 1986 amnesty is what made his training by al Qaeda possible. Had Abouhalima not been given permanent residency, he would not have been able to travel abroad and become a trained terrorist.

The case of Mohammed Salameh, who rented the truck used in the 1993 World Trade Center bombing, shows why an amnesty will not hinder terrorists. His application for amnesty was denied because he was not as adept at making fraudulent claims as was Abouhalima. The INS did its job in his case and rejected his application on its face. However, because there is no mechanism in place to force people who are denied a green card to leave the country, he continued to live and work in the United States illegally and ultimately take part in terrorism. Thus, in the past terrorists who applied for amnesty either received it, making their operations easier, or, when turned down, simply continued to engage in terrorism unhindered. In sum, the last amnesty only helped terrorists and did nothing to hinder those involved in the first World Trade Center bombing. If we are to have an amnesty, then at the very least we first need to devote a great deal more resources to interior enforcement, including detention space and INS agents assigned to investigate applications and to detain and remove those found ineligible.


Although the national security, economic, and fiscal arguments against illegal immigration are overwhelming, many people still might argue that there is little that can be done about this situation. In fact, the problem isn't nearly as intractable as it may seem. The INS estimates that each year roughly 150,000 illegal aliens leave the country on their own, another 200,000 or so get green cards as part of the normal "legal" immigration process, 50,000 illegals are deported, and about 20,000 die. In sum, at least 400,000 people leave the illegal‑alien population each year.

Of course, something like 800,000 new illegals arrive annually, and thus the total illegal population continues to grow. But the numbers leaving the illegal population are still huge, and we can use this fact to our advantage. If we significantly reduce the number of new illegal aliens entering the country and increase the number who go home, even if only modestly, we can engineer an annual decline in the illegal‑alien population, allowing the problem to become progressively smaller over time through attrition.4

Strict enforcement of immigration laws at consulates overseas, at ports of entry, at the border, and especially in the interior of the United States is one of the most effective means we have of reducing the threat from foreign‑born terrorists. Failure to develop a vigorous interior enforcement system will result in the continual increase of the illegal alien population, imposing significant costs on unskilled American workers, taxpayers, and, in the long‑run, American business. By enforcing immigration laws we can improve the lives of the working poor, save taxpayers money, and help reduce the terrorist threat.

End Notes

1 A copy of a Census Bureau report can be found on line at:

2 A copy of the Center's terrorism report can be found on line at:

3 Smith, James P. and Barry Edmonston, eds. 1997 "The New Americans: Economic, Demographic, and Fiscal of Immigration," Washington DC: National Academy Press.

4 The report, authored by Robert Warren, can be found on line at: