A person who acquires a foreign citizenship by applying for it may lose U.S. citizenship. In order to lose U.S. citizenship, the law requires that the person must apply for the foreign citizenship voluntarily, by free choice, and with the intention to give up U.S. citizenship.
In 1967 when the Supreme Court handed down its decision in Afroyim v. Rusk , 387 U.S. 253. In that decision, the court declared unconstitutional the provisions of Section 349(a) which provided for loss of nationality by voting in a foreign election.
In so doing, the Supreme Court indicated that a U.S. citizen "has a constitutional right to remain a citizen... unless he voluntarily relinquishes that citizenship."
Further confirmation of the necessity to establish the citizen's intent to relinquish nationality before expatriation will result came in the opinion in Vance v. Terrazas , 444 U.S. 252 (1980).
The Court stated that "expatriation depends on the will of the citizen rather than on the will of Congress and its assessment of his conduct."
The Court also indicated that a person's intention to relinquish U.S. citizenship may be shown by statements or actions.