The wave of immigration from eastern and southern Europe between 1890 and 1914 prompted strenuous efforts to restrict immigration. Labor unions worried that an oversupply of cheap labor would drive down wages. Native-born whites, whose Protestant ancestors had arrived generations earlier, feared that the newer, primarily Jewish and Catholic immigrants endangered their moral and cultural values. In 1917 Congress enacted legislation to reduce the influx of foreigners. The new law included the following provisions outlining who should be denied entry.

Sec. 3. That the following classes of aliens shall be excluded from admission into the United States: All idiots, imbeciles, feeble-minded persons, epileptics, insane persons; persons who have had one or more attacks of insanity at any time previously; persons of constitutional psychopathic inferiority; persons with chronic alcoholism; paupers; professional beggars; vagrants; persons afflicted with tuberculosis in any form or with a loathsome or dangerous contagious disease; persons not comprehended within any of the foregoing excluded classes who are found to be and are certified by the examining surgeon as being mentally or physically defective, such physical defect being of a nature which may affect the ability of such alien to earn a living; persons who have been convicted of or admit having committed a felony or other crime or misdemeanor involving moral turpitude; polygamists, or persons who practice polygamy or believe in or advocate the practice of polygamy; anarchists, or persons who believe in or advocate the overthrow by force or violence of the Government of the United States, or of all forms of law, or who disbelieve in or are opposed to organized government, or who advocate the assassination of public officials, or who advocate or teach the unlawful destruction of property; persons who are members of or affiliated with any organization entertaining and teaching disbelief in or opposition to organized government, or who advocate or teach the duty, necessity, or propriety of the unlawful assaulting or killing of any officer or officers, either of specific individuals or of officers generally, of the Government of the United States or of any other organized government, because of his or their official character, or who advocate or teach the unlawful destruction of property; prostitutes, or persons coming into the United States for the purpose of prostitution or for any other immoral purpose; persons who directly or indirectly procure or attempt to procure or import prostitutes or persons for the purpose of prostitution or for any other immoral purpose; persons who are supported by or receive in whole or in part the proceeds of prostitution; persons hereinafter called contract laborers, who have been induced, assisted, encouraged, or solicited to migrate to this country by offers or promises of employment, whether such offers or promises are true or false, or in consequence of agreements, oral, written or printed, express or implied, to perform labor in this country of any kind, skilled or unskilled; persons who have come in consequence of advertisements for laborers printed, published, or distributed in a foreign country; persons likely to become a public charge; persons who have been deported under any of the provisions of this Act, and who may again seek admission within one year from the date of such deportation, unless prior to their reembarkation at a foreign port or their attempt to be admitted from foreign contiguous territory the Secretary of Labor shall have consented to their reapplying for admission; persons whose tickets or passage is paid for with the money of another, or who are assisted by others to come, unless it is affirmatively and satisfactorily shown that such persons do not belong to one of the foregoing excluded classes; persons whose ticket or passage is paid for by any corporation, association, society, municipality, or foreign Government, either directly or indirectly; stowaways, except that any such stowaway, if otherwise admissible, may be admitted in the discretion of the Secretary of Labor; all children under sixteen years of age, unaccompanied by or not coming to one or both of their parents, except that any such children may, in the discretion of the Secretary of Labor, be admitted if in his opinion they are not likely to become a public charge and are otherwise eligible.

Source: Immigration Act of 1917, 39 Stat. 875–76 (1917).