Chapter 3 - USCIS Authority to Naturalize
It has long been established that Congress has the exclusive authority under its constitutional power to establish a uniform rule of naturalization and to enact legislation under which citizenship may be conferred upon persons.  Before 1991, naturalization within the United States was a judicial function exercised since 1790 by various courts designated in statutes enacted by Congress under its constitutional power to establish a uniform rule of naturalization.
As of October 1, 1991, Congress transferred the naturalization authority to the Attorney General (now the Secretary of DHS).  USCIS is authorized to perform such acts as are necessary to properly implement the Secretary’s authority.  In certain cases, an applicant for naturalization may choose to have the Oath of Allegiance  administered by USCIS or by an eligible court with jurisdiction. Eligible courts may choose to have exclusive authority to administer the Oath of Allegiance.
1. [^] See Chirac v. Chirac, 15 U.S. 259 (1817).
8 CFR 2 - Authority of the Secretary of the Department of Homeland Security
INA 318 - Prerequisite to naturalization, burden of proof
No appendices available at this time.
Technical Update - Replacing the Term “Foreign National”October 08, 2019
This technical update replaces all instances of the term “foreign national” with “alien” throughout the Policy Manual as used to refer to a person who meets the definition provided in INA 101(a)(3) [“any person not a citizen or national of the United States”].
POLICY ALERT - Comprehensive Citizenship and Naturalization Policy GuidanceJanuary 07, 2013
USCIS is issuing updated and comprehensive citizenship and naturalization policy guidance in the new USCIS Policy Manual.