C ongress's power to establish rules for the admission of non-U.S. nationals (aliens ) has long been viewed as plenary. In the Immigration and Nationality Act (INA), as amended, Congress has specified various grounds for the exclusion or removal of aliens, including grounds related to the commission of criminal conduct. Some criminal offenses committed by an alien who is present in the United States may render that alien subject to removal from the country. And certain offenses may preclude an alien outside the United States from either being admitted into the country or being permitted to reenter following an initial departure. Further, committing certain crimes may disqualify an alien from many forms of relief from removal, prevent an alien from adjusting to lawful permanent resident (LPR) status, or bar an LPR from naturalizing as a U.S. citizen. This report provides an overview of the major immigration consequences of criminal activity. The report begins by briefly discussing the laws governing the immigration consequences of criminal conduct and the government entities charged with administering U.S. immigration laws. Next, the report enumerates specific crimes and categories of crimes that may render an alien inadmissible or deportable. Then, the report discusses the potential impact criminal activity may have for an alien's eligibility to obtain various forms of relief from removal or exclusion, including relief through a waiver of application of certain grounds for removal, cancellation of removal, voluntary departure, asylum, or withholding of removal. Next, the report discusses criminal activity affecting an alien's ability to adjust to LPR status or naturalize as a U.S. citizen. Finally, the report examines select legal issues related to the intersection of criminal law and immigration, including the responsibilities of criminal defense attorneys representing alien defendants, as well as judicial interpretation of particular INA provisions that may render aliens who have been convicted of certain crimes removable. The INA primarily governs the administration of U.S. immigration laws. Originally enacted in 1952, the INA unified the country's immigration laws under one umbrella framework. A number of federal agencies possess distinct responsibilities relating to the administration of the country's immigration laws, including the Department of Justice, the State Department, and, following the enactment of the Homeland Security Act of 2002, the Department of Homeland Security (DHS). Before Congress enacted the Homeland Security Act most U.S. immigration laws—particularly as they related to enforcement activities and providing relief or services to aliens within the United States—were primarily administered by the Attorney General, who largely delegated his power to two agencies within the Department of Justice (DOJ): the Immigration and Naturalization Service (INS), which carried out enforcement and service activities, and the Executive Office for Immigration Review (EOIR), which carried out adjudication activities. The Homeland Security Act, as relevant here, dismantled the INS, created DHS, and transferred many of the Attorney General's immigration administration responsibilities to the DHS Secretary. Thus, the DHS Secretary is now "charged with the administration and enforcement of [the INA] and all other laws relating to the immigration and naturalization of aliens, except insofar as this chapter or such laws relate to the powers, functions, and duties conferred upon the President, Attorney General" and other executive officers. Three components of DHS—Customs and Border Protection (CBP), Immigration and Customs Enforcement (ICE), and U.S. Citizenship and Immigration Services (USCIS)—carry out the major functions of the former INS. In particular, ICE is the primary investigative arm of immigration enforcement within the United States. When ICE determines that an alien located within the U.S. interior has violated the immigration laws—for example, by committing certain crimes—DHS typically apprehends the alien and initiates removal proceedings against him before an immigration judge (IJ) within DOJ's EOIR. CBP, on the other hand, is authorized to enforce immigration laws at the border, which involves responsibilities including the inspection and admission of aliens seeking entry into the United States and the expedited removal of certain inadmissible aliens apprehended at or near the border while seeking entry to the United States. DHS, through USCIS, also plays a role in determining eligibility and approving applications for certain forms of relief and immigration benefits (e.g., granting asylum, adjusting status, or naturalizing). Despite the transfer of most enforcement functions to DHS, removal proceedings are primarily conducted by EOIR within DOJ. During those proceedings, an IJ typically assesses an alien's removability and eligibility for relief from removal. At the removal hearing—a civil proceeding —aliens generally have a right to legal counsel at their own expense. An IJ makes an initial removability determination, which may be appealed to the Board of Immigration Appeals (BIA), the highest administrative body charged with interpreting and applying federal immigration laws. (The Attorney General is vested with discretion to review those appeals as well.) Additionally, as was the case before enactment of the Homeland Security Act, Attorney General rulings "with respect to all questions of law shall be controlling." Federal circuit courts of appeals have exclusive jurisdiction to adjudicate petitions for review of final removal orders issued in proceedings before EOIR. However, the INA limits what issues the appellate courts may review. For instance, the INA limits federal courts' jurisdiction over cases involving an alien ordered removed based on certain criminal activity, unless the alien raises a constitutional claim or question of law (e.g., whether particular conduct an alien allegedly committed is of the type of conduct covered by a particular removal ground in the INA). Another executive branch agency, the State Department, takes the lead role in processing the visas that aliens must generally obtain (with notable exceptions) to travel to, and be admitted into, the United States. Immigrant visas are granted to aliens seeking lawful permanent residency in the United States, whereas nonimmigrant visas are issued to aliens seeking temporary admission into the United States. In both cases, the alien seeking a visa must submit supporting documentation to, and interview with, a consular official who generally must be located in the country where the alien resides. Eligibility for a particular visa depends on specified criteria set forth in the INA. And, as will be discussed in further detail below, certain criminal activity may render an alien ineligible to obtain a visa to enter the United States. Aliens who commit certain crimes may be ineligible to enter or remain in the United States. The term "inadmissible" is used to describe aliens who are generally ineligible to receive visas or otherwise be lawfully admitted into the United States. "Deportable" refers to aliens who have been lawfully admitted to the United States, but have engaged in proscribed activities that render them removable from the country. The criminal grounds for inadmissibility are primarily set forth in INA § 212(a)(2). The criminal grounds are a mix of specific crimes and categories of crimes with varying levels of proof required for the crime to render an alien inadmissible. Criminal grounds for deportation are primarily listed in INA § 237(a)(2). Like the inadmissibility grounds, criminal deportation grounds also consist of specific crimes and categories of crimes. One main difference between the criminal grounds for inadmissibility and deportability is that the deportability grounds largely require the alien to have been convicted of the listed offense, whereas the inadmissibility grounds for certain crimes may only require that the alien admitted committing the offense or that immigration authorities have "reason to believe" the alien committed the proscribed conduct. Both the criminal grounds of inadmissibility and deportability under the INA reference a "crime of moral turpitude" as one of the bases for denying admission or deporting an alien from the United States. The federal courts and legal community have long grappled over the meaning of the term "crime involving moral turpitude" (alternatively referred to as "crime of moral turpitude"). Neither the INA nor any earlier immigration law defines the term. Some federal appellate courts have opined that the term's legislative history, or lack thereof, "leaves no doubt ... that Congress left the term 'crime involving moral turpitude' to future administrative and judicial interpretation." According to the BIA, moral turpitude "refers generally to conduct that shocks the public conscience as being inherently base, vile, or depraved, and contrary to accepted rules of morality and the duties owed between persons and to society in general." In addition, moral turpitude, according to the BIA, involves "malicious intention" and actions "contrary to justice, honesty, principle, or good morals." The federal courts generally agree that a crime that is inherently fraudulent or involves an intent to defraud is a crime involving moral turpitude. It is less settled, however, when other, nonfraudulent crimes constitute crimes involving moral turpitude. Indeed, before Attorney General Michael Mukasey's 2008 opinion in Matter of Silva-Trevino ( Silva - Tr e vino I ), which set forth a standard for assessing whether a crime involved moral turpitude, there had been an "absence of an authoritative administrative methodology for resolving moral turpitude inquiries [which had] resulted in different approaches across the country." In Silva-Tr e vino I, the Attorney General ruled that a crime involving moral turpitude must involve both reprehensible conduct and a culpable mental state, such as specific intent, deliberateness, or recklessness. Since then, the BIA has adopted this formulation as the standard for determining whether an offense constitutes a crime involving moral turpitude. INA § 101(a)(43) provides a list of crimes deemed to be aggravated felonies for immigration purposes; a list which Congress has repeatedly expanded over the years to cover additional crimes. The list includes many specific offenses, as well as several broad categories of crimes.