Mr. Chief Justice Warren
delivered the opinion of the Court.
In this, the third of the denationalization cases decided today, issues concerning Section 401 (c) of the Nationality Act of 1940 are presented. That statute provides:
“A person who is a national of the United States, whether by birth or naturalization, shall lose his nationality by:
“(c) Entering, or serving in, the armed forces of a foreign state unless expressly authorized by the laws of the United States, if he has or acquires the nationality of such foreign state . ...”
We need not in this case consider the constitutionality of Section 401 (c). This case thus differs from Perez v. Brownell, ante, p. 44, and Trop v. Dulles, ante, p. 86, where questions of the constitutionality of Sections 401 (e) and 401 (g) were determined. The issues with which we are concerned here relate solely to problems of burden of proof.
Petitioner brought this action in a District Court praying for a judgment declaring him to be a citizen of the United States. The controversy arose from petitioner’s application to a United States Consulate in Japan for an American passport. Instead of the passport, he received more than a year later a Certificate of the Loss of the Nationality of the United States. Petitioner alone testified at the trial, the Government introducing no testimony. What follows is a summary of his testimony.
Petitioner was born in Artesia, California, in 1916. By reason of that fact, he was a citizen of the United States, and because of the citizenship of his parents, he was also considered by Japan to be a citizen of that country. Petitioner was educated in the schools of this country and lived here until 1939. In August of that year, having been graduated from the University of California with a degree in engineering, he went to Japan, intending to stay between two and five years, visiting and studying. He knew that his father had registered him in the family register in Japan. In November of 1939 petitioner’s father, who was paying his way, died in this country and petitioner, lacking funds, went to work for an aircraft manufacturing company in Japan for the equivalent of $15 a month. He was unable to accumulate any savings. Pursuant to the Military Service Law of Japan, petitioner was required about June 1940 to take a physical examination, and on March 1, 1941, he was inducted into the Japanese Army. The Military Service Law provided for imprisonment for evasion. Between the time of his physical examination and his induction, petitioner did not protest his induction or attempt to renounce his Japanese nationality, to return to the United States or to secure the aid of United States consular officials. He testified that he was told by a friend who worked at the American Embassy that the American Consulate could not aid a dual national; the Government has not contended that this was not so. He further testified that he had heard rumors about the brutality of the Japanese secret police which made him afraid to make any protest.
Petitioner testified that he did not know when he went to Japan that he was likely to be drafted. He said he was not aware at that time of any threat of war between the United States and Japan. He had left the United States just prior to the outbreak of war in Europe and two years and four months before Pearl Harbor. He testified that he was unable to read the Japanese language and lived too far out in the country to subscribe to an English-language newspaper, and therefore did not read any newspapers while in Japan.
Petitioner served as a maintenance man or mechanic in an Air Force regiment in China, Indo-China, the Philippines and Manchuria. He testified that when war between the United States and Japan began, he expressed the opinion to a group of noncommisioned officers that there was no chance of Japan’s winning the war. That night he was given a thorough beating; he was beaten almost every day for a month, and afterwards he was beaten “a couple days a month.” He won the nickname “America.”
After hearing this testimony, the district judge announced from the bench that “the court simply does not believe the testimony of the witness. That is all. I simply do not believe his testimony.” He went on to express his opinion that petitioner “went over because as a Japanese citizen under the laws of Japan it was necessary for him to serve his hitch in the army. . . . He went over and he waited until they reached him on the draft, and when they did he was drafted.” Formally, the court found as a fact on the basis of petitioner’s testimony alone, which did not include an admission to that effect, that his “entry and service in the Japanese Armed Forces was his free and voluntary act.” Therefore he was held to have lost his nationality under Section 401 (c) and judgment was rendered for respondent. The Court of Appeals for the Ninth Circuit affirmed that judgment. We granted certiorari. 352 U. S. 907.
Whatever divergence of view there may be as to what conduct may, consistent with the Constitution, be said to result in loss of nationality, cf. Perez v. Brownell, ante, pp. 44, 62, it is settled that no conduct results in expatriation unless the conduct is engaged in voluntarily. Mandoli v. Acheson, 344 U. S. 133. The Government does not contend otherwise. Likewise, the parties are agreed that when a citizenship claimant proves his birth in this country or acquisition of American citizenship in some other way, the burden is upon the Government to prove an act that shows expatriation by clear, convincing and unequivocal evidence. In Oonzales v. London, 350 U. S. 920, we held that the rule as to burden of proof in denaturalization cases applied to expatriation cases under Section 401 (j) of the Nationality Act of 1940. We now conclude that the same rule should govern cases under all the subsections of Section 401.
The parties disagree as to whether the Government must also prove that the expatriating act was voluntarily performed or whether the citizenship claimant bears the burden of proving that his act was involuntary. Petitioner contends that voluntariness is an element of the expatriating act, and as such must be proved by the Government. The Government, on the other hand, relies upon the ordinary rule that duress is a matter of affirmative defense and contends that the party claiming that he acted involuntarily must overcome a presumption of voluntariness.
Because the consequences of denationalization are so drastic petitioner’s contention as to burden of proof of voluntariness should be sustained. This Court has said that in a denaturalization case, “instituted ... for the purpose of depriving one of the precious right of citizenship previously conferred we believe the facts and the law should be construed as far as is reasonably possible in favor of the citizen.” Schneiderman v. United States, 320 U. S. 118, 122. The same principle applies to expatriation cases, and it calls for placing upon the Government the burden of persuading the trier of fact by clear, convincing and unequivocal evidence that the act showing renunciation of citizenship was voluntarily performed. While one finds in the legislative history of Section 401, and particularly Section 401 (c), recognition of the concept of voluntariness, there is no discussion of the problem of the burden of proof. What is clear is that the House Committee which considered the bill rejected a proposal to enact a conclusive presumption of voluntariness in the case of dual nationals entering or serving in the military forces of the nation of their second nationality. It is altogether consonant with this history to place upon the Government the burden of proving vol-untariness. The Court has said that “Rights of citizenship are not to be destroyed by an ambiguity.” Perkins v. Elg, 307 U. S. 325, 337. The reference was to an ambiguity in a treaty, but the principle there stated demands also that evidentiary ambiguities are not to be resolved against the citizen.
Finally, the Government contends that even if it has the burden of proving voluntariness by clear, convincing and unequivocal evidence, that burden has been met in this case. What view the District Court took of the burden of proof does not clearly appear. The Court of Appeals seemed at one point to accept the evidence in the District Court as sufficient even on the view of the burden of proof as above stated. That conclusion is not supportable. Of course, the citizenship claimant is subject to the rule dictated by common experience that one ordinarily acts voluntarily. Unless voluntariness is put in issue, the Government makes its case simply by proving the objective expatriating act. But here petitioner showed that he was conscripted in a totalitarian country to whose conscription law, with its penal sanctions, he was subject. This adequately injected the issue of voluntariness and required the Government to sustain its burden of proving voluntary conduct by clear, convincing and unequivocal evidence. The Government has not sustained that burden on this record. The fact that petitioner made no protest and did not seek aid of American officials — efforts that, for all that appears, would have been in vain — does not satisfy the requisite standard of proof. Nor can the district judge’s disbelief of petitioner’s story of his motives and fears fill the evidentiary gap in the Government’s case. The Government’s only affirmative evidence was that petitioner went to Japan at a time when he was subject to conscription.
On this record the Government has not established the voluntary conduct that is the essential ingredient of expatriation. The fact that this petitioner, after being conscripted, was ordered into active service in wartime on the side of a former enemy of this country must not be permitted to divert our attention from the necessity of maintaining a strict standard of proof in all expatriation cases. When the Government contends that the basic right of citizenship has been lost, it assumes an onerous burden of proof. Regardless of what conduct is alleged to result in expatriation, whenever the issue of voluntariness is put in issue, the Government must in each case prove voluntary conduct by clear, convincing and unequivocal evidence.
The judgment of the Court of Appeals is reversed and the cause is remanded to the District Court for further proceedings consistent with this opinion.
Reversed and remanded.
54 Stat. 1168, 1169. The present provision, Immigration and Nationality Act of 1952, § 349 (a) (3), 66 Stat. 267, 268, 8 U. S. C. § 1481 (a)(3), eliminates the necessity that the expatriate have or acquire the nationality of the foreign state.
235 F. 2d 135.
See also, e. g., Acheson v. Murata, 342 U. S. 900; Acheson v. Okimura, 342 U. S. 899; Dos Reis ex rel. Camara v. Nicolls, 161 F. 2d 860; 41 Op. Atty. Gen., No. 16.
Baumgartner v. United States, 322 U. S. 665; Schneiderman v. United States, 320 U. S. 118.
Gonzales v. London, 350 U. S. 920; Acheson v. Murata, 342 U. S. 900, and Acheson v. Okimura, 342 U. S. 899, are not dispositive of the issue. The holding in Gonzales went to the Government’s burden of proof in general without specific regard to voluntariness. Murata and Okimura came here on appeal from a District Court’s holding that various subsections of § 401 were unconstitutional. 99 F. Supp. 587, 591. We remanded for specific findings as to the circumstances attending the alleged acts of expatriation and the reasonable inferences to be drawn therefrom.
In Bruni v. Dulles, 98 U. S. App. D. C. 358, 235 F. 2d 855, the Court of Appeals for the District of Columbia Circuit considered Gonzales as requiring the Government to prove voluntariness by clear, convincing and unequivocal evidence. Lehmann v. Acheson, 206 F. 2d 592, can also be read as placing that burden on the Government. It is clear, at least, that the Third Circuit, Lehmann v. Acheson, supra; Perri v. Dulles, 206 F. 2d 586, as well as the Second Circuit, Augello v. Dulles, 220 F. 2d 344, regards conscription as creating a presumption of involuntariness which the Government must rebut. The Court of Appeals for the District of Columbia Circuit took a contrary view prior to Bruni v. Dulles, supra. Alata v. Dulles, 95 U. S. App. D. C. 182, 221 F. 2d 52; Acheson v. Maenza, 92 U. S. App. D. C. 85, 202 F. 2d 453.
See also United States v. Minker, 350 U. S. 179, 197 (concurring opinion): “When we deal with citizenship we tread on sensitive ground.”
See Hearings before the House Committee on Immigration and Naturalization on H. R. 6127, superseded by H. R. 9980, 76th Cong., 1st Sess. 150, 201.
The proposal was advanced by the State Department spokesman, Mr. Flournoy, who said:
“If a man is a citizen of the United States and Japan, both countries, as he would be in all of these cases we have been discussing, and he is living in Japan, and he reaches the military age, and they call him for service, it should not make any difference from our point of view whether he makes a protest or not. It is his duty to serve. He is in that country, and he is a citizen of that country, and if we accept his plea of duress in these cases it practically nullifies the whole thing, so we should put a proviso in reading somewhat as follows: That if an American national also has the nationality of a foreign country and is residing therein at a time when he reaches the age for liability of military service his entry into the armed forces thereof shall be presumed to be voluntary. In other words, a plea of duress would not make any difference. He is a citizen of that country, and he is presumed to know that when the time comes he will have to serve.” Id., at 150.
Spokesmen for the Labor and Justice Departments objected, stating that dual nationals should have the opportunity to be heard on the question of duress. Id,., at 150-156; 169-170; 200-203. At the time of the hearings § 401 (c) was not limited to dual nationals. The Senate Committee inserted the limitation. See 86 Cong. Rec. 12817.
The Court of Appeals for the First Circuit has correctly concluded that little significance attaches to the failure of the House Committee to accept a suggestion that the word “voluntarily” be inserted in subsections (b) through (g) of §401. Hearings, supra, at 397-398. “It seems to us that the failure of the committee to accept this amendment is of little significance in view of the legislative history . . . indicating that such amendment was unnecessary and superfluous.” Dos Reis ex rel. Camara v. Nicolls, 161 F. 2d 860, 864, n. 4.
235 F. 2d, at 140. But see id., at 141.
Petitioner’s evidence of conscription also dispelled the presumption created by § 402 of the Nationality Act of 1940, 54 Stat. 1169, that a national who remains six months or more within the country of which either he or his parents have been nationals, has expatriated himself under §401 (c) or (d). Even if valid, “Section 402 does not enlarge §401 (c) or (d),” Kawakita v. United States, 343 U. S. 717, 730, and, like the analogous provision of § 2 of the Act of March 2, 1907, 34 Stat. 1228, it creates “a presumption easy to preclude, and easy to overcome.” United States v. Gay, 264 U. S. 353, 358. The ambiguous terms of § 402 have since been superseded by § 349 (b) of the Immigration and Nationality Act of 1952, 66 Stat. 268, 8 U. S. C. § 1481 (b), which establishes a conclusive presumption of voluntariness on the part of a dual national who performs an expatriating act if he had resided in the state of his second nationality an aggregate of ten years or more immediately prior thereto. Of course, the new statutory presumption is not in issue in this case and there is no need to consider its validity.