	Introduction

It is estimated that there are more than 11 million unauthorized aliens currently living in the United States, and the resident unauthorized alien population is estimated to increase by 500,000 people per year. In addition, each year approximately 1 million aliens are apprehended while trying to illegally enter the United States. Although most of these aliens are entering the United States for economic opportunities or fleeing civil strife and political unrest, some are criminals, and some may be terrorists. The report continues with a discussion of the role of state and local law enforcement in the enforcement of immigration laws. What is Immigration Enforcement? Immigration enforcement is the regulation of those who violate provisions of the Immigration and Nationality Act (INA). This includes violations of the civil provisions of the INA (e.g., aliens who enter without inspection or violate the conditions of their admittance), as well as U.S. citizens or aliens who violate the criminal provisions of the INA (e.g., marriage fraud or alien smuggling). However, increasing the immigration enforcement role of other federal agencies is controversial and could distract the agencies from their primary missions. In FY1992, 433 workyears were spent locating and arresting criminal aliens. In FY2003, the number of workyears devoted to criminal alien cases was 740, almost double the amount of hours spent on these cases in FY1992. In FY2003, 23% of all hours (435 workyears) were devoted to administrative and non-investigative tasks. Comparison

 Figure 14 illustrates that many more resources (measured in staff hours) have been allotted to enforcement between the ports of entry than enforcement within the United States and at the ports of entry. Historically, Congress and INS devoted five times more resources (staff and funding) to border enforcement than to interior enforcement. CBP received the inspections functions and the border patrol. Conclusion

Many duties are incorporated under the banner of immigration enforcement. These include removing aliens who should not be in the United States, investigating alien smuggling and trafficking, patrolling between and at ports of entry, combating document and benefit fraud, and enforcing the prohibitions against employers hiring aliens without work authorization. However, others assert that the United States has not tried immigration enforcement, arguing that most of the resources have been devoted to border enforcement, and that the United States has not fully engaged in other types of immigration enforcement, most notably worksite enforcement. The majority of aliens come to the United States for economic opportunities and for family reunification. Thus, some argue that only a guest worker program, creating opportunities for a large number of immigrants to come to the United States to work, could significantly reduce the unauthorized migration. However, others argue that better worksite enforcement and enforcement document fraud would make it more difficult for unauthorized aliens to find work, resulting in a decrease in the unauthorized population.
An estimated 11 million unauthorized aliens reside in the United States, and this population is estimated to increase by 500,000 annually. Each year, approximately 1 million aliens are apprehended trying to enter the United States illegally. Although most of these aliens enter the United States for economic opportunities and family reunification, or to avoid civil strife and political unrest, some are criminals, and some may be terrorists. All are violating the United States' immigration laws.
Immigration enforcement is the regulation of those who violate provisions of the Immigration and Nationality Act (INA). This includes violations of the INA's civil provisions (e.g., violate the conditions of their admittance), as well as U.S. citizens or aliens who violate the criminal provisions (e.g., marriage fraud or alien smuggling). Many divergent tasks are incorporated under the banner of immigration enforcement. These include removing aliens who should not be in the United States, investigating alien smuggling and trafficking, patrolling between and at ports of entry, combating document and benefit fraud, and enforcing the prohibitions against employers hiring aliens without work authorization.
Historically, more resources (measured in staff hours) have been allotted to enforcement at the border than enforcement within the United States. While the amount of U.S. Border Patrol (USBP) resources almost doubled between FY1997 and FY2003, time spent on other enforcement activities increased only slightly, while the number of inspection hours decreased. Furthermore, focusing on "interior" enforcement, in FY2003, the largest amount of staff time was devoted to locating and arresting criminal aliens (39%), followed by administrative and non-investigative duties (23%) and alien smuggling investigations (15%). Only 4% was devoted to worksite enforcement (i.e., locating and arresting aliens working without authorization, and punishing employers who hire such workers).
Congress has spent much time debating immigration enforcement and the unauthorized alien population. Congress could allocate more resources to immigration enforcement activities, raising the question of what is the most efficient allocation of resources among the different enforcement tasks. For example, some assert that the United States has not truly tried immigration enforcement, arguing that most of the resources have been devoted to border enforcement, instead of fully engaging in other types of immigration enforcement; others contend that only a legalization program can reduce the unauthorized population. In addition, Congress could expand the immigration enforcement role of other federal agencies and state and local law enforcement. Many fear, however, that this option will distract the agencies and local law enforcement from their primary missions. Since many of the unauthorized aliens come to the United States for economic opportunities, some argue that a guest worker program, creating opportunities for a large number of aliens to come to the United States to work, could significantly reduce unauthorized migration. Others argue that an increase in the enforcement of the prohibition against hiring illegal alien workers and the use and manufacturing of fraudulent documents would make it more difficult for unauthorized aliens to find work, resulting in a decrease in the unauthorized population. This report will not be updated.