8 U.S.C. § 1481 : US Code - Section 1481: Loss of nationality by native-born or naturalized citizen; voluntary action; burden of proof; presumptions

Search 8 U.S.C. § 1481 : US Code - Section 1481: Loss of nationality by native-born or naturalized citizen; voluntary action; burden of proof; presumptions

(a) A person who is a national of the United States whether by
birth or naturalization, shall lose his nationality by voluntarily
performing any of the following acts with the intention of
relinquishing United States nationality - 
(1) obtaining naturalization in a foreign state upon his own
application or upon an application filed by a duly authorized
agent, after having attained the age of eighteen years; or
(2) taking an oath or making an affirmation or other formal
declaration of allegiance to a foreign state or a political
subdivision thereof, after having attained the age of eighteen
years; or
(3) entering, or serving in, the armed forces of a foreign
state 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; or
(4)(A) accepting, serving in, or performing the duties of any
office, post, or employment under the government of a foreign
state or a political subdivision thereof, after attaining the age
of eighteen years if he has or acquires the nationality of such
foreign state; or (B) accepting, serving in, or performing the
duties of any office, post, or employment under the government of
a foreign state or a political subdivision thereof, after
attaining the age of eighteen years for which office, post, or
employment an oath, affirmation, or declaration of allegiance is
required; or
(5) making a formal renunciation of nationality before a
diplomatic or consular officer of the United States in a foreign
state, in such form as may be prescribed by the Secretary of
State; or
(6) making in the United States a formal written renunciation
of nationality in such form as may be prescribed by, and before
such officer as may be designated by, the Attorney General,
whenever the United States shall be in a state of war and the
Attorney General shall approve such renunciation as not contrary
to the interests of national defense; or
(7) committing any act of treason against, or attempting by
force to overthrow, or bearing arms against, the United States,
violating or conspiring to violate any of the provisions of
section 2383 of title 18, or willfully performing any act in
violation of section 2385 of title 18, or violating section 2384
of title 18 by engaging in a conspiracy to overthrow, put down,
or to destroy by force the Government of the United States, or to
levy war against them, if and when he is convicted thereof by a
court martial or by a court of competent jurisdiction.
(b) Whenever the loss of United States nationality is put in
issue in any action or proceeding commenced on or after September
26, 1961 under, or by virtue of, the provisions of this chapter or
any other Act, the burden shall be upon the person or party
claiming that such loss occurred, to establish such claim by a
preponderance of the evidence. Any person who commits or performs,
or who has committed or performed, any act of expatriation under
the provisions of this chapter or any other Act shall be presumed
to have done so voluntarily, but such presumption may be rebutted
upon a showing, by a preponderance of the evidence, that the act or
acts committed or performed were not done voluntarily.