This is a bit flashbacky, but in June 2002, John Yoo, then the deputy chief of the Justice Department’s Office of Legal Counsel, considered the question of what
“„An individual who voluntarily “enter[s], or serv[es] in, the armed forces of a foreign state”(13)may be expatriated, “if (A) such armed forces are engaged in hostilities against the United States, or (B) such persons serve as a commissioned or non-commissioned officer.” 8 U.S.C. § 1481(a)(3). Nonetheless, no person may be expatriated unless he acts “with the intention of relinquishing United States nationality.” 8 U.S.C. § 1481(a). That said, although the performance of an expatriating act cannot be used as “the equivalent of or as conclusive evidence of the indispensable voluntary assent of the citizen,” such conduct “may be highly persuasive evidence in the particular case of a purpose to abandon citizenship.” Terrazas, 444 U.S. at 261 (quotations omitted).
“„Voluntary service in a foreign armed force that is engaged in hostilities against the United States has frequently been viewed as a particularly strong manifestation of an intention to abandon citizenship. As Attorney General Clark once opined, “it is highly persuasive evidence, to say the least, of an intent to abandon United States citizenship if one enlists voluntarily in the armed forces of a foreign government engaged in hostilities against the United States.” 42 Op. Att’y Gen. at 401. *See also *22 C.F.R. § 50.40(a) (although “intent to retain U.S. citizenship will be presumed” when an individual “naturalize[s] in a foreign country” or “take[s] a routine oath of allegiance,” no such presumption is provided “[i]n other loss of nationality cases”).