Now I've got to do some reading.
Well, geez, that already tells me that it has to do with Aliens and Nationality...the actual name of Title (USC) 8.
Congress provided specific legislative authority for nullifying citizenship when, in 1907, it enacted the predecessor of the modern federal expatriation statute. See Act of Mar. 2, 1907, ch. 2534, 34 Stat. 1228 (1907). As the Supreme Court has noted, such acts of Congress "are to be read in the light of [Congress's 1868] declaration of policy favoring freedom of expatriation which stands unrepealed." Savorgnan v. United States, 338 U.S. 491, 498-99 (1950).
This is coming from...@www.justice.gov/olc/expatriation.htm the cached page
@Expatriation Act 1868 nullified (first link)
Also here...@8 U.S.C. § 1481 note (2000) (first link)
Do I need to continue?