http://travel.state.gov/law/citizenship/citizenship_778.html

POTENTIALLY EXPATRIATING STATUTES

Section 349 of the Immigration and Nationality Act, as amended, states that U.S. citizens are subject to loss of citizenship if they perform certain acts voluntarily and with the intention to relinquish U.S. citizenship. Briefly stated, these acts include:

(1) obtaining naturalization in a foreign state (Sec. 349 (a) (1) INA);

(2) taking an oath, affirmation or other formal declaration to a foreign state or its political subdivisions (Sec. 349 (a) (2) INA);

(3) entering or serving in the armed forces of a foreign state engaged in hostilities against the U.S. or serving as a commissioned or non-commissioned officer in the armed forces of a foreign state (Sec. 349 (a) (3) INA);

(4) accepting employment with a foreign government if (a) one has the nationality of that foreign state or (b) a declaration of allegiance is required in accepting the position (Sec. 349 (a) (4) INA);

(5) formally renouncing U.S. citizenship before a U.S. consular officer outside the United States (sec. 349 (a) (5) INA);

(6) formally renouncing U.S. citizenship within the U.S. (but only "in time of war") (Sec. 349 (a) (6) INA);

(7) conviction for an act of treason (Sec. 349 (a) (7) INA).

ADMINISTRATIVE STANDARD OF EVIDENCE