The AAO notes that "[t]he applicable law for transmitting citizenship to a child born abroad when one parent is a U.S. citizen is the statute that was in effect at the time of the child's birth" See Chau v. Immigration and Naturalization Service, 247 F.3d 1026, 1028 n.3 (9th Cir. 2001)
The applicable law for derivative citizenship purposes is "the law in effect at the time the critical events giving rise to eligibility occurred." Minasyan v. Gonzales, 401 F.3d 1069, 1075 (9th Cir. 2005); accord Jordon v. Attorney General, 424 F.3d 320, 328 (31d Cir. 2005).
A person may only obtain citizenship in strict compliance with the statutory requirements imposed by Congress. INS v. Pangilinan, 486 U.S. 875, 884 (1988). Moreover, "it has been universally accepted that the burden is on the alien applicant to show his eligibility for citizenship in every respect." Berenyi v. District Director, INS, 385 U.S. 630, 637 (1967). The applicant must meet this burden by establishing the claimed citizenship by a preponderance of the evidence. 8 C.F.R. 341.2(c).
8 CFR 341.2
(c) Proof. The burden of proof shall be upon the claimant, or his parent or guardian if one is acting in his behalf, to establish the claimed citizenship by a preponderance of the evidence.
INA 341 [CITE: 8 USC 1452]
TITLE 8--ALIENS AND NATIONALITY
CHAPTER 12--IMMIGRATION AND NATIONALITY
SUBCHAPTER III--NATIONALITY AND NATURALIZATION
Part II--Nationality Through Naturalization [Substitute Secretary of Homeland Security for Attorney General] [Substitute USCIS for "the Service"]
INA 341 [8 USC 1452]. Certificates of citizenship or U.S. non-citizen national status; procedure
(a) Application to Attorney General for certificate of citizenship; proof; oath of allegiance
A person who claims to have derived United States citizenship through the naturalization of a parent or through the naturalization or citizenship of a husband, or who is a citizen of the United States by virtue of the provisions of section 1993 of the United States Revised Statutes, or of section 1993 of the United States Revised Statutes, as amended by section 1 of the Act of May 24, 1934 (48 Stat. 797), or who is a citizen of the United States by virtue of the provisions of subsection (c), (d), (e), (g), or (i) of section 201 of the Nationality Act of 1940, as amended (54 Stat. 1138), or of the Act of May 7, 1934 (48 Stat. 667), or of paragraph (c), (d), (e), or (g) of section 1401 of this title, or under the provisions of the Act of August 4, 1937 (50 Stat. 558), or under the provisions of section 203 or 205 of the Nationality Act of 1940 (54 Stat. 1139), or under the provisions of section 1403 of this title, may apply to the Attorney General for a certificate of citizenship. Upon proof to the satisfaction of the Attorney General that the applicant is a citizen, and that the applicant's alleged citizenship was derived as claimed, or acquired, as the case may be, and upon taking and subscribing before a member of the Service within the United States to the oath of allegiance required by this chapter of an applicant for naturalization, such individual shall be furnished by the Attorney General with a certificate of citizenship, but only if such individual is at the time within the United States.