Illegal entry and presence in the United States without authorization violate US civil immigration law and are punishable by removal from the country and other civil law penalties. The act of entering the United States without authorization (illegal entry) and the act of reentering after deportation (illegal reentry) are also federal crimes. Both offenses have existed as federal crimes in various forms since the early 20th century, but the sentences, rates of prosecution, and justifications for prosecution have changed over the years.
Illegal Entry and Reentry Crimes
Under US federal law, at 8 US Code Section 1325, a non-citizen who enters or seeks to enter the United States at a place other than a port of entry, or by fraud or false documents, commits a federal misdemeanor offense that is punishable by up to six months in prison. A subsequent conviction for illegal entry can be punishable by up to two years.
Under 8 US Code Section 1326, reentering or being found in the United States without authorization after deportation constitutes felony illegal reentry. The non-citizen must have been formally removed before he or she reentered; he or she cannot have left the United States voluntarily.
Over the years, Congress has amended the illegal reentry statute to increase the maximum penalties for different categories of defendants. In 1952, the maximum punishment for all people convicted of illegal reentry was two years in prison. In 1986, the Immigration Reform Act upped the maximum penalty to 20 years in prison for defendants who reenter the United States after prior convictions for aggravated felonies (lower maximum sentences apply to defendants with other prior criminal convictions). “Aggravated felony” in this context is defined in the same broad way as it is in the Immigration and Nationality Act, and can include nonviolent crimes and even state misdemeanors that match one of the many enumerated crimes. These changes reflect a change in the justification for these prosecutions: the penalties have increased as legislators’ focus has shifted from deterring illegal reentry to targeting dangerous criminals who might commit new crimes in the US, with the existence of a prior criminal record serving as a proxy for dangerousness.
As Figure I demonstrates, prosecutions for illegal entry and reentry have increased significantly over the past decade. For most of the 1990s, relatively few border-crossers were charged with illegal entry. Prosecutions jumped dramatically in 2004, and under President Barack Obama, the surge has continued.  Although illegal entry prosecutions have dropped slightly from a historic high of 54,000 in 2009, the level of prosecutions remains high. Illegal reentry prosecutions have increased dramatically as well, albeit more steadily.
Immigration cases now outnumber all other types of federal criminal cases filed in US district court. These cases do not include the tens of thousands of first-time illegal entry cases that conclude in federal magistrate court.
What the Federal Sentencing Guidelines Say
Sentences within the federal criminal system are calculated according to guidelines promulgated by the US Sentencing Commission. The Commission is charged with developing guidelines to achieve “reasonable uniformity” among sentences for the same offenses, as well as “proportionality in sentencing through a system that imposes appropriately different sentences for criminal conduct of differing severity.”
In 2005, the Supreme Court ruled in United States v. Booker that the sentencing guidelines were not mandatory and that judges have the discretion to depart from these guidelines. Judges, however, must still consult the guidelines, and according to a 2012 report by the Commission, “[t]he sentencing guidelines have remained the essential starting point in all federal sentences and have continued to exert significant influence on federal sentencing trends over time.”
The sentencing guidelines apply to felonies and Class A misdemeanors (misdemeanors for which the maximum sentence is one year or less but more than six months). Sentencing guideline 2L1.2, for “Unlawfully Entering or Remaining in the United States,” applies to defendants convicted of felony illegal reentry or a second or subsequent charge of misdemeanor illegal entry.
Guideline sentences are calculated based on a combination of the “offense level” and the defendant’s criminal history. The offense level for an illegal entry offense is based on the defendant’s prior conviction or convictions. Guideline 2L1.2 treats certain prior criminal convictions—for crimes of violence, drug trafficking (for which a sentence of 13 months or more was imposed), child pornography, firearms offenses, national security or terrorism offenses, human trafficking, or alien smuggling—as most serious, warranting a significant 16-level increase in offense level. Other prior convictions result in increases of 4, 8, or 12 offense levels.
The defendant’s criminal history category is determined based on the number and seriousness of the defendant’s prior convictions, with I being least serious (including those with no or one minor prior conviction) and VI being most serious. Convictions that are more than 15 years old are generally not counted in assigning the defendant to a criminal history category, though they do count for the offense level.
The offense level and the criminal history category are considered together to come up with a “guideline” sentence. For example, a defendant with one prior felony conviction for illegal reentry, for which he received a sentence of six months, who was then arrested for a second illegal reentry offense while on supervised release (i.e., probation), would be at offense level 12 and criminal history category III, and face a guideline sentence of 15 to 21 months. A defendant with one prior aggravated assault conviction who served one year in prison would be at offense level 24 and criminal history category II, and thus face a guideline sentence of 57-71 months. For all federal crimes, a defendant who pleads guilty will typically get a reduction in offense level for “acceptance of responsibility,” and many defendants accept “Fast-Track” plea deals in which they receive a significant reduction in offense levels in exchange for a waiver of certain rights. So the above calculations are based on what defendants would face if they were convicted at trial.
In 2010, the US Sentencing Commission amended the sentencing guideline for “unlawfully entering or remaining in the United States” to recognize “cultural assimilation” as a valid reason for granting a lower-than-guideline sentence, to be considered in cases where, in part, “those cultural ties provided the primary motivation for the defendant’s illegal reentry or continued presence in the United States.” The provision, however, has not necessarily led to more “departures” from the guidelines (more lenient criminal sentences). (For more information, see section III: Criminal Prosecutions Impinge on the Rights to Family Unity and to Seek Asylum.)
The guideline for illegal entry offenses has been criticized by many criminal defense attorneys and some judges for being excessively harsh, and by some former and current assistant US attorneys for being vague and difficult to apply.
Who is Being Prosecuted for Illegal Entry and Reentry?
Individuals convicted of immigration offenses (the vast majority of whom are convicted of illegal entry and reentry) come from very different populations than individuals convicted of other federal crimes. According to data received by the US Sentencing Commission, 88 percent of defendants convicted of immigration offenses in 2012 were Hispanic, while only 31 percent of defendants convicted of other federal crimes were Hispanic. Eighty-two percent of immigration offenders did not finish high school, while 37 percent of other federal offenders did not finish high school.
Among illegal entry cases prosecuted in district court in 2010 (which excludes the 40,000-plus cases processed in magistrate court), 86 percent of defendants were men. The majority of defendants were under age 35, but 32 percent were 35 to 49 years old. Among illegal reentry cases, 97 percent of defendants were men, 42 percent were between 25 and 34 years old, and another 41 percent were 35 to 49. In 2010, of the 23,489 defendants charged with illegal entry or reentry in US district court, 32 illegal entry defendants and 50 illegal reentry defendants were US citizens. Seventy percent of illegal entry defendants and 85 percent of illegal reentry defendants were Mexican nationals.
Relevant Border Patrol Policies
Non-citizens apprehended entering the United States without authorization are expelled from the country in a number of different ways.
Border Patrol agents sometimes allow a non-citizen to depart voluntarily without going through a formal removal (that is, deportation). Processing time is shortest for voluntary return, and the non-citizen will not face any immigration penalties, such as a bar from entering the US at a later date. In 2011, 324,000 individuals were returned in this manner or granted voluntary departure, a substantial decrease from 10 years earlier, when over 1 million individuals were returned voluntarily.
If a non-citizen is ordered removed—that is, deported—he or she faces penalties under both immigration law and federal criminal law if he or she tries to reenter.
If a non-citizen is deported through “expedited removal,” which does not require an order by an immigration judge, he or she is barred from the United States for five years. If a non-citizen is ordered removed by an immigration judge, or accepts “stipulated removal,” he or she is barred from the United States for 10 or 20 years, depending on the number of removals; he or she is barred for life if ordered removed for an “aggravated felony.” If a non-citizen tries to return to the US illegally after removal, he or she is subject to prosecution for illegal reentry.
The Obama administration deported a record 1.6 million non-citizens through such formal removals between fiscal year 2009 and 2012.
Referrals for Criminal Prosecution and Operation Streamline
Both US Customs and Border Protection (CBP) and US Immigration and Customs Enforcement (ICE) are empowered to refer unauthorized immigrants for federal criminal prosecution before formally deporting them. CBP refers significantly more cases. In 2012, CBP referred 86 percent of all illegal entry cases and 46 percent of all illegal reentry cases; ICE referred 1 percent of illegal entry and 25 percent of illegal reentry cases.
Before 2005, CBP only referred non-citizens with criminal records or repeat offenders for criminal prosecution. Others, including first-time migrants, were returned or removed. In 2005, however, that policy changed with the advent of Operation Streamline in Del Rio, Texas. Touted as a “zero-tolerance” program toward all non-citizens caught crossing the border without authorization, CBP claimed that they were prosecuting nearly everyone they apprehended in the Del Rio sector.  CBP no longer promotes Streamline as a “zero-tolerance” program, and CBP does not come close to referring every migrant apprehended for criminal prosecution; immigration authorities in 2010 made about 17 federal criminal arrests per 100 apprehensions in Southwest Border Patrol sectors.  Rather, CBP describes criminal prosecution as one option in its “consequence delivery system,” which is designed to “uniquely evaluate each subject and apply the appropriate post-arrest consequences … to break the smuggling cycle and end the subject’s desire to attempt further illegal entry.” 
Operation Streamline is active in many, but not all, federal courts in the Western and Southern Districts of Texas, New Mexico, and Arizona, making the Southern District of California the only exception among states on the southern border. Ninety-eight percent of prosecutions for illegal entry and seventy-seven percent of prosecutions for illegal reentry in 2012 were in the four judicial districts in which Streamline is active. Not all of these prosecutions take place in the mass hearings characteristic of Streamline, but the push to prosecute is clearly greatest in the districts in which Streamline is active. A large number of prosecutions used to occur in the Southern District of California, but there has been a significant drop in recent years: the 2,727 cases prosecuted in the district accounted for just 3 percent of all illegal entry and reentry cases in 2012. Of those cases, only 206 were for illegal entry, representing just 0.4 percent of all illegal entry prosecutions. In districts elsewhere in the country, there are only a couple of dozen prosecutions each year.
 Immigration and Nationality Act Section 275, 8 US Code Section 1325 (2012).
 Immigration and Nationality Act Section 276, 8 US Code Section 1326 (2012).
 See Doug Keller, “Re-thinking Illegal Entry and Re-entry,” Loyola University Chicago Law Journal, vol. 44, Fall 2012.
 See Immigration and Nationality Act Section 101(a)(43), 8 US Code Section 1101(a)(43) (2012).
 See Keller, “Rethinking Illegal Entry and Re-entry,” Fall 2012.
 Transactional Records Access Clearinghouse (TRAC), “Lead Charges for Criminal Immigration Prosecutions: FY 1986-FY 2011,” 2011, http://trac.syr.edu/immigration/reports/251/include/imm_charges.html (accessed April 12, 2013).
Executive Office of US Attorneys, “Annual Statistical Reports,” 2002-2012, http://www.justice.gov/usao/reading_room/foiamanuals.html (accessed April 15, 2013). In 2012, immigration cases made up 40.6 percent of criminal cases filed. Eighty-five percent of “immigration cases” involved illegal entry or reentry charges. Administrative Office of US Courts, Caseload Statistics 2012, “Table D-2: Defendants Commenced, by Major Offenses, 2008 through 2012,” http://www.uscourts.gov/Statistics/FederalJudicialCaseloadStatistics/FederalJudicialCaseloadStatistics2012.aspx (accessed May 6, 2013). Because drug cases often involve several defendants, the total number of defendants charged for drug offenses in US district courts in 2012 (31,739) was higher than the number of defendants charged with immigration offenses in US district court (26,572).
 US Sentencing Commission, 2012 Sentencing Guidelines Manual, http://www.ussc.gov/Guidelines/2012_Guidelines/index.cfm (accessed April 12, 2013).
United States v. Booker, 543 U.S. 220 (2005).
 US Sentencing Commission, “Report on the Continuing Impact of US v. Booker on Federal Sentencing,” 2012, http://www.ussc.gov/Legislative_and_Public_Affairs/Congressional_Testimony_and_Reports/Booker_Reports/2012_Booker/Part_A.pdf (accessed April 25, 2013).
 18 US Code Section 3559(a)(6) (2012).
 US Sentencing Guideline 2L1.2, Unlawfully Entering or Remaining in the United States (2012).
 Ibid. A conviction for a drug trafficking offense for which the sentence imposed was 13 months or less results in an increase of 12 levels; a conviction for an aggravated felony, 8 levels; a conviction for any other felony, 4 levels; and convictions for three or more misdemeanors that are crimes of violence or drug trafficking offenses, 4 levels (with some variations for older offenses).
 US Sentencing Guideline 4A1.1 (2012).
 See US Sentencing Commission, 2012 Federal Sentencing Guidelines Manual, “Sentencing Table,” http://www.ussc.gov/Guidelines/2012_Guidelines/Manual_PDF/Sentencing_Table.pdf (accessed April 7, 2013).
 US Sentencing Guideline 3E1.1 (2012) (“Acceptance of Responsibility”); Memorandum for all US Attorneys from James M. Cole, deputy attorney general, US Department of Justice, “Department Policy on Early Disposition or ‘Fast-Track’ Programs,” January 31, 2012, http://www.justice.gov/dag/fast-track-program.pdf (accessed April 7, 2013).
 US Sentencing Guideline 2L1.2.
 See Keller, “Rethinking Illegal Entry and Reentry,” Fall 2012. Thirty-four percent of federal judges surveyed in 2010 agreed that guideline sentences for these offenses are too long. US Sentencing Commission, “Results of Survey of United States District Judges from January 2010 to March 2010,” June 2010, http://www.ussc.gov/Research/Research_Projects/Surveys/20100608_Judge_Survey.pdf (accessed April 7, 2013). See also Caleb E. Mason &Scott M. Lesowitz, “A Rational Post-Booker Proposal for Reform of Federal Sentencing Enhancements for Prior Convictions,” Northern Illinois University Law Review, 2011, http://www.niu.edu/law/organizations/law_review/pdfs/full_issues/31_2/Mason_6.pdf (accessed May 10, 2013).
US Sentencing Commission, 2012 Sourcebook, “Table 46: Demographic and Offense Information for Immigration Offenses,” http://www.ussc.gov/Data_and_Statistics/Annual_Reports_and_Sourcebooks/2012/Table46.pdf (accessed April 16, 2013).
Mark Motivans, US Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, “Immigration Offenders in the Federal Criminal System, 2010,” July 2012, http://bjs.gov/index.cfm?ty=pbdetail&iid=4392 (accessed April 12, 2013), p. 22.
 Testimony of Michael J. Fisher, chief, US Border Patrol, US Customs and Border Protection (CBP), before US House of Representatives, Committee on Homeland Security, Subcommittee on Border and Maritime Security, October 4, 2011, http://www.dhs.gov/news/2011/10/04/written-testimony-cbp-house-homeland-security-subcommittee-border-and-maritime (accessed April 14, 2013).
 American Immigration Council, Immigration Policy Center, “A Decade of Rising Immigration Enforcement,” http://www.immigrationpolicy.org/just-facts/decade-rising-immigration-enforcement (accessed April 25, 2013). This figure includes individuals who received “voluntary departure,” a form of relief from removal granted by immigration judges. However, in fiscal year 2011, immigration judges granted voluntary departure in 30,385 cases, a small number compared to the almost 300,000 returned voluntarily by Border Patrol. US Department of Justice, Executive Office of Immigration Review, Office of Planning, Analysis, and Technology, “FY 2011: Statistical Year Book,” February 2012, http://www.justice.gov/eoir/statspub/fy11syb.pdf (accessed April 22, 2013).
 Immigration and Nationality Act Section 212(a)(9)(A)(i) (2012).
 Immigration and Nationality Act Section 212(a)(9)(A)(ii) (2012).
 US Immigration and Customs Enforcement (ICE), “Removal Statistics,” http://www.ice.gov/removal-statistics (accessed April 12, 2013).
 Transactional Records Access Clearinghouse (TRAC), “Going Deeper” tool, Prosecutions filed by agency, 2012, http://tracfed.syr.edu/index/index.php?layer=cri (accessed May 10, 2013). See also TRAC, “Continued Decline and Shifting Focus Seen in Criminal Immigration Prosecutions,” November 19, 2012, http://trac.syr.edu/immigration/reports/300/ (accessed April 14, 2013).
 Joanna Lydgate, “Assembly-Line Justice: A Review of Operation Streamline,” The Chief Justice Earl Warren Institute on Race, Ethnicity, and Diversity, University of California, Berkeley Law School, January 2010, http://www.law.berkeley.edu/files/Operation_Streamline_Policy_Brief.pdf (accessed April 25, 2013).
 Human Rights Watch meeting with US Customs and Border Protection, February 23, 2013; Motivans, “Immigration Offenders in the Federal Justice System, 2010,” July 2012, http://bjs.gov/index.cfm?ty=pbdetail&iid=4392p. 8.
 US Customs and Border Protection, “2012-2016: Border Patrol Strategic Plan,” http://nemo.cbp.gov/obp/bp_strategic_plan.pdf (accessed April 12, 2013).
 TRAC, “Express” tool, Prosecutions under 8 USC Section 1325 and 1326 by judicial district, from fiscal year 2008 to 2012, http://tracfed.syr.edu/index/index.php?layer=cri (accessed May 10, 2013).