Section 212 (a) of the Immigration and Nationality Act reads as follows:
Classes of Excludable Aliens - Except as otherwise provided in this Act, the following describes classes of excludable aliens who are ineligible to receive visas and who shall be exclude from admission into the United states.

(1) HEALTH - RELATED GROUNDS.--
(A) IN GENERAL. -- Any Alien--
(i) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services) to have a communicable disease of public health significance,
(ii) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services in consultation with to Attorney General)--
(I) to have a physical or mental disorder and behavior associated with the disorder that may pose, or has posed, a threat to the property, safety, or welfare of the alien or others, or
(II) to have a physical or mental disorder and a history of behavior associated with the disorder which behavior has posed a threat to the property, safety, or welfare of the alien or others and which behavior is likely to recur or to lead to other harmful behavior or
(iii) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services) to be a drug abuser or addict, is excludable.
(B) WAIVER AUTHORIZED.-- For provisions authorizing waiver of certain clauses of subparagraph (A), see subsection (g).

(2) CRIMINAL AND RELATED GROUNDS.--
(A) CONVICTION OF CERTAIN CRIMES.--
(i) IN GENERAL.-- Except as provided in a clause (ii), any alien convicted of, or who admits having committed, or who admits acts which constitute the essential elements of--
(I) a crime involving moral turpitude (other than a purely political offense), or
(II) a violation of (or a conspiracy to violate) any law or regulation of a State, the United States, or a foreign country relating to a controlled substance (as defined in section 102 of the Controlled Substances Act (21 U.S.C. 802)), is excludable.
(ii) EXCEPTION.-- clause (i)(I) shall not apply to an alien who committed only one crime if--
(I) the crime was committed when the alien was under 18 years of age and the crime was committed (and the alien released from any confinement to a prison or correctional institution imposed for the crime) more than 5 years before the date of application for visas or other documentation and the date of application for admission to the United States, or
(II) the maximum penalty possible for the crime of which the alien was convicted (or which the alien admits having committed or of which the acts that the alien admits having committed constituted the essential elements) did not exceed imprisonment for one year and, the alien was not sentenced to a term of imprisonment in excess of 6 months (regardless of the extent to which the sentence was ultimately executed).
(B) MULTIPLE CRIMINAL CONVICTIONS.-- Any alien convicted of 2 or more offenses (other than purely political offenses), regardless of whether the conviction was in a single trial or whether the offenses arose from a single scheme of misconduct and regardless of whether the offenses involved moral turpitude, for which the aggregate sentences to confinement actually imposed were 5 years or more is excludable.
(D) PROSTITUTION AND COMMERCIALIZED VICE.-- Any alien who--
(i) is coming to the United States solely, principally, or incidentally to engage in prostitution, or has engaged in prostitution within 10 years of the date of application for a visa, entry, or adjustment of status,
(ii) directly or indirectly procures or attempts to procure, or (within 10 years of the date of application for a visa, entry, or adjustment of status)
procured or attempted to procure or to import, prostitutes or persons for the purpose of prostitution, or receives or (within such 10-year period) received, in whole or in part, the proceeds of prostitution, or
(iii) is coming to the United States to engage in any other unlawful commercialized vice whether or not related to prostitution, is excludable.
(E) CERTAIN ALIENS INVOLVED IN SERIOUS CRIMINAL ACTIVITY WHO HAVE ASSERTED IMMUNITY FROM PROSECUTION.--Any alien--
(i) who has committed in the United States at any time a serious criminal offense (as defined in section 101(h)),
(ii) for whom immunity from criminal jurisdiction was exercised with respect to that offense,
(iii) who as a consequence of the offense and exercise of immunity has departed from the United States, and
(iv) who has not subsequently submitted fully to the jurisdiction of the court in the United States having jurisdiction with respect to that offense, is excludable.
(F) WAIVER AUTHORIZED.-- For provisions authorizing waiver of certain subparagraphs of this paragraph, see subsection (h).

(3) SECURITY AND RELATED GROUNDS.--
(A) IN GENERAL.-- Any alien who a consular officer or the Attorney General knows, or has reasonable ground to believe, seeks to enter the United States to engage solely, principally, or incidentally in--
(i) any activity to violate any law of the United States relating to espionage or sabotage or to violate or evade any law prohibiting the export from the United States of goods, technology, or sensitive information,
(ii) any other unlawful activity, or
(iii) any activity a purpose of which is the opposition to, or the control or overthrow of, the Government of the United States by force, violence, or other unlawful means, is excludable.
(B) TERRORIST ACTIVITIES. --
(i) IN GENERAL.-- Any alien who--
(I) has engaged in terrorist activity, or
(II) a consular officer of the Attorney General knows, or has reasonable ground to believe, is likely to engage after entry in any terrorist activity (as defined in clause (iii)), is excludable.
An alien is an officer, official, representative, or spokesman of the Palestine Liberation Organization is considered, for purpose of this Act, to be engaged in a terrorist activity.
(ii) TERRORIST ACTIVITY DEFINED.-- As used in this Act, the term 'terrorist activity' means any activity which is unlawful under the laws of the place where it is committed (or which, if committed in the United States, would be unlawful under the laws of the United States or any State) and which involves any to the following:
(I) The hijacking or sabotaging of any conveyance (including aircraft, vessel, or vehicle).
(II) The seizing or detaining, and threatening to kill, injure, or continue to detain, another individual in order to compel a third person(including a governmental organization) to do or abstain from doing any act as an explicit or implicit condition for the release of the individual seized or detained.
(III) A violent attack upon an internationally protected person (as defined in section 1116 (b)(4) of title 18, United States Code) or upon the liberty of such a person.
(IV) An assassination
(V) The use of any--
(a) biological agent, chemical agent, or nuclear weapon or device, or
(b) explosive or firearm (other than for mere personal monetary gain), with the intent to endanger, directly or indirectly, the safety of one or more individuals or to cause substantial damage to property.
(VI) A threat, attempt, or conspiracy to do any of the foregoing.
(iii) ENGAGE IN TERRORIST ACTIVITY DEFINED.-- As used in this Act, the term 'engage in terrorist activity' means to commit, in an individual capacity or as a member of an organization, an act which the actor knows or reasonably should know, afford material support to an individual organization or government in conducting a terrorist activity at any time, including any of the following acts;
(I) The preparation or planning of a terrorist activity.
(II) The gathering of information on potential targets for terrorist activity.
(III) The Providing of any type of material support, including a safe house, transportation, communications, funds, false identification, weapons, explosives, of training, to any individual the actor knows or has reason to believe has committed or plans to commit a terrorist activity.
(IV) The soliciting of funds or other things of value for terrorist activity or for any terrorist organization.
(V) Tho solicitation of any individual for membership in a terrorist organization, terrorist government, or to engage in a terrorist activity.
(C) FOREIGN POLICY.--
(i) IN GENERAL.-- An alien whose entry or proposed activities in the United States the Secretary of State has reasonable ground to believe would have potentially serious adverse foreign policy consequences for the United States is excludable.
(ii) EXCEPTIONS FOR OFFICIALS.-- An alien who is an official of a foreign government or a purported government, or who is a candidate for election to a foreign government office during the period immediately preceding the election for that office, shall not be excludable or subject to restrictions or conditions on entry into the United States under clause (i) solely because of the alien's past, current, or expected beliefs, statements, or associations, if such belief, statements, or associations would be lawful within the United States.

(iii) EXCEPTIONS FOR OTHER ALIENS.-- An alien, not described in clause (ii) shall not be excludable or subject to restrictions or conditions on entry into the United States under clause (i) because of the alien's past, current, or expected beliefs, statements, or associations, would be lawful within the United States, unless the Secretary of State personally determines that the alien's admission would compromise a compelling United States foreign policy interest
(iv) NOTIFICATION OF DETERMINATIONS.-- If a determination is made under clause (iii) with respect to an alien, the Secretary of State must notify on a timely basis the chairman of the committees on the Judiciary and Foreign Affairs of the House of Representatives and of the Committees on the Judiciary and Foreign Relations of the Senate of the identity of the alien and the reasons for the determination.
(D) IMMIGRANT MEMBERSHIP IN TOTALITARIAN PARTY.--
(i) IN GENERAL.-- Any immigrant who is or has been a member of or affiliated with the Communist or any other totalitarian party (or subdivision or affiliate thereof), domestic or foreign, is excludable.
(ii) EXCEPTION FOR INVOLUNTARY MEMBERSHIP.-- clause (i) shall not apply to an alien because of membership or affiliation if the alien establishes to the satisfaction of the consular officer when applying for a visa (or to the satisfaction of the Attorney General when applying for admission) that the membership or affiliation is or was involuntary, or is or was solely when under 16 years of age, by operation of law, or for purposes of obtaining employment, food, rations, or other essentials of living whether necessary for such purposes.
(iii) EXCEPTION FOR PAST MEMBERSHIP.-- Clause (i) shall not apply to an alien because of membership or affiliation if the alien establishes to the satisfaction of the consular officer when applying for a visa (or to the satisfaction of the Attorney General when applying for admission) that--
(I) the membership or affiliation terminated at least--
(a) 2 years before the date of such application,or
(b) 5 years before the date of such application, in the case of an alien whose membership or affiliation was with the party controlling the government of a foreign state that is a totalitarian dictatorship as of such date, and
(II) the alien is not a threat to the security of the United States.
(iv) EXCEPTION FOR CLOSE FAMILY MEMBERS.-- The Attorney General may, in the Attorney General's discretion, waive the application of clause (i) in the case of an immigrant who is the parent, spouse, son, daughter, brother, or sister of a citizen of the United States or a spouse, son or daughter of an alien lawfully admitted for permanent residence for humanitarian purposes, to assure family unity, or when it is otherwise in the public interest if the immigrant is not a threat to the security of the United States.
(E) PARTICIPANTS IN NAZI PERSECUTIONS OR GENOCIDE.--

(i) PARTICIPATION IN NAZI PERSECUTIONS.-- Any alien who, during the period beginning on March 23, 1933, and ending on May 8, 1945, under the direction of, or in association with--
(I) the Nazi government of Germany
(II) any government in any area occupied by the military forces of the Nazi government of Germany,
(III) any government established with the assistance or cooperation of the Nazi government of Germany, or
(IV) any government which was an ally of the Nazi government of Germany, or incited, assisted, or otherwise participated in the persecution of any person because of race, religion, national origin, or political opinion is excludable.
(ii) PARTICIPATION IN GENOCIDE.-- Any alien who has engaged in conduct that is defined as genocide for purposes of the International Convention on the Prevention and Punishment of Genocide is excludable.

(4) PUBLIC CHARGE.-- Any alien who, in the opinion of the consular officer at the time of application for a visa, or in the opinion of the Attorney General at the time of application for admission or adjustment of status, likely to become a public charge is excludable.

(5) LABOR CERTIFICATION AND QUALIFICATIONS FOR CERTAIN IMMIGRANTS.
-- (A) LABOR CERTIFICATION.--
(I) IN GENERAL.-- Any alien who seeks to enter the United States for the purpose of performing skilled or unskilled labor is excludable, unless the Secretary of Labor has determined and certified to the Secretary of State and the Attorney General that--
(I) there are not sufficient workers who are able, willing, qualified (or equally qualified in the case of an alien described in clause (ii) and available at the time of application for a visa and admission to the United States and at the place where the alien is to perform such skilled or unskilled labor, and
(II) the employment of such alien will not adversely affect the wages and working conditions in the United States similarly employed.
(ii) CERTAIN ALIENS SUBJECT TO SPECTIAL RULE.-- For purposes of clause (i)(I), an alien described in this clause is an alien who--
(I) is a member of the teaching profession, or
(II) has exceptional ability in the sciences or the arts.


(B) UNQUALIFIED PHYSICIANS.-- An alien who is a graduate of a medical school not accredited by a body or bodies approved for the purpose by the secretary of Education (regardless of whether such school or medicine is in the United States) and who is coming to the United States principally to perform services as a member of the medical profession is excludable, unless the alien (i) has passed parts I and II of the National Board of Medical Examiners Examination (or an equivalent examination as determined by the Secretary of Health and Human Services) and (ii) is competent in oral and written English. For purposes of the previous sentence, an alien who is a graduate of a medical school shall be considered to have passed parts I and II of the National Board of Medical Examiners if the alien was fully and permanently licensed to practice medicine in a State on January 9, 1978, and was practicing medicine in a State on that date.
(C) APPLICATION OF GROUNDS.-- The grounds for exclusion of aliens under subparagraph (A) and (B) shall apply to immigrants seeking admission or adjustment of status under paragraphs (2) or (3) of Section 203(b).

(6) ILLEGAL ENTRANTS AND IMMIGRATION VIOLATORS.--
(A) ALIENS PREVIOUSLY DEPORTED.-- Any alien who has been excluded from admission and deported and who again seeks admission within one year of the date of such deportation is excludable, unless prior to the alien's reembarkation at a place outside the United States or attempt to be admitted from foreign contiguous territory the Attorney General has consented to the alien's reapplying for admission.
(B) CERTAIN ALIENS PREVIOUSLY REMOVED.-- Any alien who--
(i) has been arrested and deported,
(ii) has fallen into distress and has been removed pursuant to this or any prior Act,
(iii) has been removed as an alien enemy, or
(iv) has been removed at Government expense in lieu of deportation pursuant to section 242(b), and (a) who seeks admission within 5 years of the date of such deportation or removal or (b) who seeks admission within 20 years in the case of an alien convicted of an aggravated felony, is excludable, unless before the date of the alien's embarkation or reembarkation at a place outside the United states or attempted to be admitted from foreign contiguous territory the Attorney General has consented to the alien's applying or reapplying for admission.
(C) MISREPRESENTATION--
(i) IN GENERAL-- Any alien who, by fraud or willfully misrepresenting a material fact, seeks to procure (or has sought to procure or has procured) a visa, other documentation, or entry into the United States or other benefit provide under this Act is excludable.
(ii) WAIVER AUTHORIZED.-- For provisions authorizing waiver of clause (i), see subsection (i).
(D) STOWAWAYS.-- Any alien who is a stowaway is excludable.
(E) SMUGGLERS.--
(i) Any alien who at any time knowingly has encouraged, induced, assisted, abetted, or aided any other alien to enter or to try to enter the United States in violation of law is excludable.
(ii) SPECIAL RULE IN THE CASE OF FAMILY REUNIFICATION.--

Clause (i) shall not apply in the case of alien who is an eligible immigrant (as defined in section 301(b)(1) of the Immigration Act of 1990), was physically present in the United States on May 5, 1988, and is seeking admission as an immediate relative or under section 203(a)(2) (including under section 112 of the Immigration of 1990) or benefit under section 301(a) of the Immigration Act of 1990 if the alien, before may 5, 1988, has encouraged, induced, assisted, abetted, or aided only the alien's spouse, parent, son, or daughter (and no other individual) to enter the United States in violation of law.
(iii) WAIVER AUTHORIZED.-- For provisions authorizing waiver of clause (i), see subsection (d)(11).
(F) SUBJECT OF CIVIL PENALTY.-- An alien who is the subject of a final order for violation of section 247C is excludable.

(7) DOCUMENTATION REQUIREMENTS.--
(A) IMMIGRATNS.--
(i) IN GENERAL.-- Except as otherwise specifically provided in this Act, any immigrant at the time of application for admission--
(I) who is not in possession of a valid immigrant visa, reentry permit, border crossing identification card, or other valid entry document required by this Act, and a valid unexpired passport, or other suitable travel document, or document of identity and nationality if such document is required under the regulations issued by the Attorney General under Section 211(a), or
(II) whose visa has been issued without compliance with the provisions of section 203, is excludable
(ii) WAIVER AUTHORIZED.-- For provisions authorizing waiver of clause (i), see subsection (k).
(B) NONIMMIGRANTS.--
(i) IN GENERAL.-- Any nonimmigrant who--
(I) is not in possession of a passport valid for a minimum of six months from the date of the expiration of the initial period of the alien's admission or contemplated initial period of stay authorizing the alien to return to the country from which the alien came or to proceed to and enter some other country during such period, or
(II) is not in possession of a valid nonimmigrant visa or border crossing identification card at the time of application for admission, is excludable.
(ii) GENERAL WAIVER AUTHORIZED.-- For provisions authorizing waiver of clause (i) see subsection (d)(4).
(iii) GUAM VISA WAIVER.-- For provision authorizing waiver of clause (i) in the case of visitors to Guam, see subsection (I).
(iv) VISA WAIVER PILOT PROGRAM.-- For authority to waive the requirements of clause (i) under a pilot program, see section 217.

(8) INELIGIBLE FOR CITIZENSHIP.--
(A) IN GENERAL.-- Any immigrant who is permanently ineligible to citizenship is excludable.

(B) DRAFT EVADERS.-- Any person who has departed from or who has remained outside the United States to avoid or evade training or service in emergency is excludable, except that this subparagraph shall not apply to an alien who at the time of such departure was a nonimmigrant and who is seeking to reenter the United States as a nonimmigrant.

(9) MISCELLANEOUS.--

(A) PRACTICING POLYGAMIST.-- Any immigrant who is coming to the United States to practice polygamy is excludable.
(B) GUARDIAN REQUIRED TO ACCOMPANY EXCLUDED ALIEN.-- Any alien accompanying another alien ordered to be excluded and deported and certified to be helpless from sickness or mental or physical disability or infancy pursuant to section 237(e), whose protection or guardianship is required by the alien ordered excluded and deported, is excludable.
(C) INTERNATIONAL CHILD ABDUCTION.--
(i) IN GENERAL.-- Except as provided in clause (ii), any alien who, after entry of an order by a court in the United States granting custody to a person of a United States Citizen child who detains or retains the child, or custody of the child outside the United States from the person granted custody by that order.
(ii) EXCEPTION.-- Clause (i) shall not apply so long as the child is located in a foreign state that is a party of the Hague Convention on the Civil Aspects of International Child Abduction.

Section 212(e) of the Immigration and Nationality Act reads as follows:
No person admitted under section 101(a)(15)(j) of this title or acquiring such status after admission (i) whose participation in the program for which he came to the United states was financed in whole or in part, directly or indirectly, by an agency of the Government of the United States or by the government of the country of his nationality of his last residence, (ii) who at the time of admission or acquisition of status under section 101(a)(15)(j) of this title was a national or resident of a country which the the Director of the U.S. Information Agency pursuant to regulations proscribed by him, had designated as clearly requiring the services of persons engaged in the field of specialized knowledge or skill in which the alien was engaged, or (iii) who came to the United states or acquired such status in order to receive graduate medical education or training, shall be eligible to apply for an immigrant visa, or for permanent residence, or for a nonimmigrant visa under sections 101(a)(15)(H), 101(a)(15)(L), of this title until it is established that such person has resided and been physically present in the country of his nationality or his last residence for an aggregate of at least two years following departure from the United States: Provided, That upon the favorable recommendation of the Director, pursuant to the request of an interested Government Agency, or of the Commissioner of Immigration and Naturalization after he has determined that departure from the United States would impose exceptional hardship upon the alien's spouse or child (if such spouse or child is a citizen of the United States or lawfully resident alien), or that the alien cannot return to the country of his nationality or last residence because he would be subject to persecution on account of race, religion, or political opinion, the Attorney General may waive the requirements of such two-year foreign residence abroad in the case of any alien whose admission to the United States is found by the Attorney General to be in the public interest: And provided further, the except in the case of an alien described in clause (iii), the Attorney General may, upon the favorable recommendation of the Director a statement in writing that it has no objection to such waiver in the case of such alien.

WAIVER OF INELIGIBILITY

Aliens who are ineligible for a visa under one of the classes enumerated above may be eligible for a waiver of ineligibility under one of the following provisions of the Act.

Section 212(g) of the Immigration and Nationality Act, provider that:
The Attorney General may waive the application of--
(1) subsection (a)(1)(A)(i) in the case of any alien who--
(A) is the spouse or the unmarried son or daughter, or the minor unmarried lawfully adopted child, or a United States citizen, or of an alien lawfully admitted for permanent residence, or of an alien who has been issued an immigrant visa, or
(B) has a son or daughter who is a United States citizen, or of an alien lawfully admitted for permanent residence, or an alien who has been issued an immigrant visa, or
(2) subsection (a)(1)(A)(ii) in the case of any alien , in accordance with such terms, conditions, and controls, if any, including the giving of bond, as the Attorney General, in his discretion after consultation with the Secretary of Health and Human Services, may by regulation prescribe.

Section 121(h) of the Immigration and Nationality Act, provides that:
The Attorney General may, in his discretion, waive the application of subparagraphs(A)(i)(I), (B), (D), and (E) of subsection (a)(2) and subparagraphs (A)(i)(II) of such subsection insofar as it relates to a single offense of simple possession of 30 grams or less of marijuana if--
(1)(A) in the case of any immigrant it is established to the satisfaction of the Attorney General that--
(i) the alien is excludable only under subparagraph (D)(i) or (D)(ii) of such section or the activities for which the alien is excludable occurred more than 15 years before the date of the alien's application for a visa, entry, or adjustment of status,
(ii) the admission to the United States of such alien would not be contrary to the national welfare, safety, or security of the United States, and
(iii) the alien has been rehabilitated; or
(B) in the case of an immigrant who is the spouse, parent, son, or daughter of a citizen of the United States or an alien lawfully admitted for permanent residence if it is established to the satisfaction of the Attorney General that the alien's exclusion would result in extreme hardship to the United States citizen or lawful resident spouse, parent, son, or daughter of such alien; and
(2) the Attorney General, in his discretion, and pursuant to such terms, conditions and procedures as he may by regulations prescribe, has consented to the alien's applying or reapplying for a visa, for admission to the United States, or adjustment of status.

No waiver shall be provided under this subsection in the case of an alien who has been convicted of (or who has admitted committing acts that constitute) murder or criminal acts involving torture.

Section 212(i) of th the Immigration and Nationality Act, provides that:
The Attorney General may, in his discretion, waive application of clause (i) of subsection (a)(6)(C)--
(1) in the case of an immigrant who is the spouse, parent, or son or daughter of a United states citizen or of an immigrant lawfully admitted for permanent residence, or
(2) if the fraud or misrepresentation occurred at least 10 years before the date of the immigrant's application for a visa, entry, or adjustment and it is established to the satisfaction of the Attorney General that the admission to the Unites States of such immigrant would not be contrary to the national welfare, safety, or security of the United States.

Section 212(d)(11) of the Immigration and Nationality Act, provides that:
The Attorney General may, in his discretion for humanitarian purposes, to assure family unity, or when it is otherwise in the public interest, waive application of clause (i) of subsection(a)(6)(E) in the case of any alien lawfully admitted for permanent residence who temporarily proceeded abroad voluntary and not under an order or deportation, and who is otherwise admissible to the United States as a returning resident under section 211(b) and in the case of an alien seeking admission or adjustment of status as an immediate relative or immigrant under section 203(a) (other than paragraph (4) thereof) if the alien has encouraged, induced, assisted, abetted or aided only the alien's spouse, parent, son, or daughter (and no other individual) to enter the United States in violation of law.

Section 212(d)(3) of the Immigration an Nationality Act, provides that:
Except as provided in this subsection, an alien (A) who is applying for a nonimmigrant visa and is know or believed by the consular officer to be ineligible for such visa under one or more of the paragraphs enumerated in subsection (q) (other than paragraphs (3)(A)(i)(I), (3)(A)(ii), (3)(A)(iii), (3)(C), or(3)(E) of such subsection), after approval by the Attorney General of a recommendation by the Secretary of State or by the consular officer that the alien be admitted temporarily despite the Secretary of State or by the consular officer that the alien be admitted into the United States temporarily as a nonimmigrant in the discretion of the Attorney General... The Attorney General shall prescribe conditions including exaction of such bonds as may be necessary to control and regulate the admission and return of excludable aliens applying for temporary admission under this paragraph.

Section 212(c) of the Immigration and Nationality Act, provides that:
Aliens lawfully admitted for permanent residence who temporarily proceed abroad voluntarily and not under an order of deportation, and who are returning to a lawful unrelinquished domicile of seven consecutive years, may be admitted in the discretion of the Attorney General without regard to the provisions of subsection (a) (other than paragraphs (3) and (9)(C)).